1 BY JUDGMENT OF 7 JANUARY 1981 , WHICH WAS RECEIVED AT THE COURT OF JUSTICE ON 14 JANUARY 1981 , THE COUR DU TRAVAIL ( LABOUR COURT ), MONS , REFERRED TO THE COURT OF JUSTICE FOR A PRELIMINARY RULING UNDER ARTICLE 177 OF THE EEC TREATY THREE QUESTIONS ON THE INTERPRETATION OF ARTICLE 51 OF REGULATION NO 1408/71 OF THE COUNCIL OF 14 JUNE 1971 ON THE APPLICATION OF SOCIAL SECURITY SCHEMES TO EMPLOYED PERSONS AND THEIR FAMILIES MOVING WITHIN THE COMMUNITY ( OFFICIAL JOURNAL , ENGLISH SPECIAL EDITION ( 1971 ) II , P . 416 ).
2 THOSE QUESTIONS AROSE IN THE CONTEXT OF PROCEEDINGS BETWEEN MR SINATRA , AN ITALIAN NATIONAL , AND THE FONDS NATIONAL DE RETRAITE DES OUVRIERS MINEURS ( NATIONAL PENSION FUND FOR MINERS ), A BELGIAN SOCIAL SECURITY INSTITUTION . SINCE 1 APRIL 1971 MR SINATRA HAS BEEN IN RECEIPT , UNDER BELGIAN LEGISLATION ALONE , OF AN INVALIDITY PENSION PAID BY THE BELGIAN INSTITUTION . APPLYING NATIONAL RULES AGAINST THE OVERLAPPING OF BENEFITS , THAT INSTITUTION DEDUCTS FROM THE BELGIAN PENSION THE AMOUNT OF THE PENSION PAID BY THE ITALIAN AUTHORITIES SINCE 1 NOVEMBER 1970 PURSUANT TO THE RELEVANT COMMUNITY RULES . BECAUSE OF THE GAINFUL EMPLOYMENT OF MR SINATRA ' S WIFE THE AMOUNT OF THE BELGIAN PENSION WAS REDUCED , WITH EFFECT FROM 1 JANUARY 1976 , TO THE ' ' SINGLE RATE ' ' . THE BELGIAN INSTITUTION CONSIDERED THAT , BY VIRTUE OF ARTICLE 51 ( 2 ) OF REGULATION NO 1408/71 , THAT ALTERATION MADE IT NECESSARY TO RECALCULATE THE BENEFITS IN ACCORDANCE WITH ARTICLE 46 OF THAT REGULATION . ON 2 NOVEMBER 1978 IT WAS INFORMED OF THE AMOUNT OF THE ITALIAN BENEFITS PAID ON 1 JANUARY 1976 AND , APPLYING BELGIAN PROVISIONS AGAINST THE OVERLAPPING OF BENEFITS AND TAKING ACCOUNT OF THE VALUE OF THAT AMOUNT AS AT 1 JANUARY 1976 , CLAIMED FROM MR SINATRA FOR THE PERIOD FROM 1 JANUARY 1976 TO 31 JANUARY 1979 AN OVERPAYMENT OF BFR 38 800 .
3 THE COUR DU TRAVAIL , MONS , CONSIDERING THAT THE OUTCOME OF THE MAIN ACTION DEPENDED UPON THE INTERPRETATION OF ARTICLE 51 OF REGULATION NO 1408/71 OF THE COUNCIL , REFERRED TO THE COURT THE FOLLOWING QUESTIONS FOR A PRELIMINARY RULING : ' ' 1 . DOES THE ' REVALORIZATION ' REFERRED TO IN THE HEADING TO ARTICLE 51 OF REGULATION NO 1408/71 OF 14 JUNE 1971 CONSTITUTE THE GENERAL FRAMEWORK OF APPLICATION OF PARAGRAPHS ( 1 ) AND ( 2 ) OF THAT ARTICLE WITH THE RESULT THAT THE CASES MENTIONED IN PARAGRAPH ( 2 ) ONLY COVER INSTANCES IN WHICH THERE IS A REVALORIZATION OR INCREASE IN BENEFITS EVEN THOUGH THE WORD ' ALTER ' USED IN ARTICLE 51 ( 2 ) USUALLY MEANS BOTH IMPROVEMENT AND DETERIORATION? 2.IS THE ' METHOD OF DETERMINING OR THE RULES FOR CALCULATING BENEFITS ' ' ALTERED ' WITHIN THE MEANING OF ARTICLE 51 ( 2 ) OF REGULATION NO 1408/71 WHERE THERE IS AN ALTERATION ONLY IN THE POSITION OF THE PERSON INSURED UNDER A SOCIAL SECURITY SCHEME WHICH REQUIRES , IN HIS CASE , APPLICATION BY THE BELGIAN INSTITUTION OF A DIFFERENT RULE OF BELGIAN LAW RELATING TO THE AMOUNT OF THE BELGIAN UNDERGROUND MINEWORKERS ' INVALIDITY PENSION AWARDED TO HIM WITH THE EFFECT OF REDUCING THE PENSION ( ARTICLE 4 ( 1 ) ( 4 ) OF THE ROYAL DECREE OF 19 NOVEMBER 1970 ), WITHOUT ANY CHANGE HAVING OCCURRED AT THAT TIME IN THE BELGIAN LEGISLATIVE PROVISIONS AS SUCH RELATING TO THE MANNER OF FIXING BENEFITS OR IN THOSE CONCERNING THE RULES FOR CALCULATING BENEFITS? 3.MUST ARTICLE 51 ( 2 ) OF REGULATION ( EEC ) NO 1408/71 BE INTERPRETED AS MEANING THAT AN ALTERATION ONLY IN THE AMOUNT OF THE INVALIDITY PENSION AWARDED BY THE COMPETENT BELGIAN INSTITUTION TO A PERSON INSURED UNDER THE SOCIAL SECURITY SCHEME WHICH HAS THE EFFECT OF REDUCING THAT AMOUNT , IN APPLICATION OF ARTICLE 4 ( 1 ) ( 4 ) OF THE ROYAL DECREE OF 19 NOVEMBER 1970 , ENTAILS A RECALCULATION OF THE BENEFITS IN ACCORDANCE WITH ARTICLE 46 OF REGULATION NO 1408/71? ' '
4 IT IS CLEAR FROM AN ANALYSIS OF THOSE QUESTIONS THAT THE NATIONAL COURT IS ESSENTIALLY SEEKING TO ASCERTAIN WHETHER , ACCORDING TO ARTICLE 51 OF REGULATION NO 1408/71 , A RECALCULATION OF BENEFITS IN ACCORDANCE WITH ARTICLE 46 OF THAT REGULATION IS NECESSARY WHERE AN ALTERATION IN THE PERSONAL CIRCUMSTANCES OF THE INSURED ENTAILS A REDUCTION IN THE BENEFITS PAID TO HIM .
5 THE SYSTEM OF AGGREGATION AND APPORTIONMENT WHICH IS PROVIDED FOR IN ARTICLE 46 OF REGULATION NO 1408/71 AND WHICH IS BASED ON ARTICLE 51 OF THE TREATY IS INTENDED TO REMEDY SITUATIONS IN WHICH THE LAWS OF ONE MEMBER STATE DO NOT BY THEMSELVES ALLOW THE PERSON CONCERNED THE RIGHT TO BENEFITS BY REASON OF THE INSUFFICIENT NUMBER OF PERIODS COMPLETED UNDER ITS LAWS , OR ONLY ALLOW HIM BENEFITS WHICH ARE LESS THAN THE MAXIMUM .
6 THAT SYSTEM MAY NOT THEREFORE BE APPLIED IF ITS EFFECT IS TO DIMINISH THE BENEFITS WHICH THE PERSON CONCERNED MAY CLAIM BY VIRTUE OF THE LAWS OF A SINGLE MEMBER STATE ON THE BASIS SOLELY OF THE INSURANCE PERIODS COMPLETED UNDER THOSE LAWS .
7 HOWEVER , WHERE THE APPLICATION OF SUCH NATIONAL LAWS PROVES LESS FAVOURABLE THAN THE APPLICATION OF THE RULES REGARDING AGGREGATION AND APPORTIONMENT THOSE RULES MUST , BY VIRTUE OF ARTICLE 46 OF REGULATION NO 1408/71 , BE APPLIED .
8 THE RIGHT THUS CONFERRED UPON THE MIGRANT WORKER TO BENEFIT FROM THE MOST FAVOURABLE SOCIAL SECURITY SYSTEM IMPLIES IN PRINCIPLE THAT , WHENEVER THERE IS AN ALTERATION IN THE BENEFITS GRANTED UNDER THAT SYSTEM , A FRESH COMPARISON BETWEEN THE NATIONAL SYSTEM AND THE SYSTEM OF AGGREGATION AND APPORTIONMENT IS TO BE CARRIED OUT IN ACCORDANCE WITH ARTICLE 46 OF REGULATION NO 1408/71 , IN ORDER TO DETERMINE WHICH SYSTEM IS THE MOST ADVANTAGEOUS FOLLOWING THE ALTERATION .
9 HOWEVER , IN ORDER TO REDUCE THE ADMINISTRATIVE BURDEN WHICH A FRESH EXAMINATION OF THE INSURED ' S SITUATION FOLLOWING EVERY ALTERATION OF BENEFITS RECEIVED WOULD REPRESENT , ARTICLE 51 OF REGULATION NO 1408/71 ESTABLISHES A DISTINCTION BETWEEN ALTERATIONS IN BENEFITS ' ' BY A FIXED PERCENTAGE OR AMOUNT ' ' RESULTING FROM ' ' AN INCREASE IN THE COST OF LIVING OR CHANGES IN THE LEVEL OF WAGES OR SALARIES OR OTHER REASONS FOR ADJUSTMENT ' ' AND ALTERATIONS IN THE ' ' METHOD OF DETERMINING ' ' OR ' ' THE RULES FOR CALCULATING ' ' BENEFITS . PARAGRAPH ( 1 ) OF THAT ARTICLE PROVIDES THAT ALTERATIONS OF THE FIRST TYPE MUST BE APPLIED DIRECTLY TO THE BENEFITS PAID WITHOUT ANY NEED FOR THE RECALCULATION EXPRESSLY PROVIDED FOR IN ARTICLE 51 ( 2 ) IN RESPECT OF ALTERATIONS OF THE SECOND TYPE .
10 THE REGULATION WAS THUS INTENDED TO EXCLUDE A FRESH CALCULATION WHERE THE ALTERATIONS IN THE BENEFITS RESULT FROM EVENTS UNCONNECTED WITH THE PERSONAL CIRCUMSTANCES OF THE INSURED AND ARE THE CONSEQUENCES OF THE GENERAL EVOLUTION OF THE ECONOMIC AND SOCIAL SITUATION .
11 SUCH EXCLUSION MAY NOT , IN THE ABSENCE OF APPROPRIATE SPECIFIC PROVISIONS , BE EXTENDED TO ALTERATIONS IN BENEFITS DUE TO A CHANGE IN THE PERSONAL CIRCUMSTANCES OF THE INSURED , SUCH AS HIS TRANSITION FROM THE ' ' HOUSEHOLD ' ' CATEGORY TO THE ' ' SINGLE ' ' CATEGORY , PARTICULARLY AS IT IS NOT POSSIBLE TO ENVISAGE AN APPLICATION , BY ANALOGY , OF ARTICLE 51 ( 1 ) IN SUCH CASES , SINCE CHANGES IN THE PERSONAL CIRCUMSTANCES OF INSURED WORKERS , AS OPPOSED TO THE ' ' REASONS FOR ADJUSTMENT ' ' REFERRED TO IN THAT PARAGRAPH , ARE NOT OF A GENERAL NATURE .
12 THEREFORE THE ANSWER TO BE GIVEN TO THE QUESTIONS RAISED BY THE COUR DU TRAVAIL , MONS , IS THAT A RECALCULATION IN ACCORDANCE WITH THE PROVISIONS OF ARTICLE 46 OF REGULATION NO 1408/71 IS NECESSARY IN RESPECT OF EACH ALTERATION IN BENEFITS PAID BY A MEMBER STATE , SAVE WHERE SUCH ALTERATION IS DUE TO ONE OF THE ' ' REASONS FOR ADJUSTMENT ' ' PROVIDED FOR IN ARTICLE 51 ( 1 ) OF REGULATION NO 1408/71 WHICH DO NOT INCLUDE SUPERVENING CHANGES IN THE PERSONAL CIRCUMSTANCES OF THE INSURED .