T-90 armor 

Please discuss. There are contradictions from the available sources.   

http://www.fas.org/man/dod-101/sys/land/row/t-90.htm
This website claims T-90A protection as follow; vs APFSDS: 550 mm + 250-280mm with Kontakt-5 = 800-830mm
vs HEAT: 650 mm + 500-700mm with Kontakt-5 = 1,150-1,350mm. This means that against APFSDS, 550mm is for T-90A Basic Armor, without Kontakt-5, and 250~280mm is for Kontakt-5. If you add this up, the sum is 800~830mm for the whole T-90A Armor. 
 doesn't know anything about what ERA is and how it works. And now he is the one who vandaling the article.