Many paint manufacturers do not always use standard colours, but instead mix their own colour shades and mixtures that are analysed and coded with an NCS code, such as 1357-Y93R. Mixtures of this type are something the paint manufacturer has produced, and the NCS code lacks an S in front of the first four digits. S in front of the numbers indicates that the code is standard, and is part of the Second Edition, 1950 standardised codes.
Many of the colours with and without S can be quite similar, but in some cases there are significant differences. Therefore we cannot use codes that are missing an S in front of the first four numbers. The paint manufacturer should be able to help you find the nearest standard NCS code if you require it.