There is a rule in IPC 7351-B, footprint naming convention where we need to shift 2 decimal places right for Body width/Lead Span/Pitch and similarly one place for chip packages.

(Example OSCCC6.7X4.2X1.5 to OSCCC670X420X150 and RESC3.4 0.8X0.6 to RESC3408X60)

Notes as per IPC naming document,

• All Lead Span and Height numbers go two places past the decimal point and “include” trailing Zeros

• All Lead Span and Body Sizes go two place before the decimal point and “remove” leading Zeros

• All Chip Component Body Sizes are one place to each side of the decimal point

• Pitch Values are two places to the right & left of decimal point with no leading Zeros but include trailing zeros

Do there any valid reason why the rule is recommended Just to follow legible naming Anyone pl help!! 

Thanks

Manuj