Is the Length of my Turnlock that I measure correspond to the quarter turn part number you suggest?

When you measure up your quarter turn turnlock stud as a total length then this never corresponds to the length number of the stud in the partnumber of the turnlock.

Often there is a misunderstanding about the length number of a Turnloc stud.

The length number is just a number and not the length in millimeters or any other physical metric.
Stud length number is used to determine the part number more accurately, for the different lengths.

If you know the length in millimeters, by measuring up your part, then you need to take with you the catalog and measure up the dimension S which is featured in the catalog.  With this S length you can then fill in the formula which is next to the drawing of the Turnlock.

example:

customer measures up S = 25mm

He sees also on the part that there is a euro symbol stamped together with the number 12

When you use the formula: S = 16.00 + (0.76 x length number)

you see on the picture: that the length number is 12, which means S = 16 + (0.76 x 12) = 25,12mm

The customer measured up himself 25mm.

if we would do reverse, and the customer cannot see the stamped number, then we have only the S length to go for, take care: in most cases in production the S length is machined with a tolerance of +/-0.5mm, which means it's not exact science

so S = 25 = 16 + (0.76 x length number) 

which means length number = (25 - 16) / 0.76 = 11.84; this number is close to length number 12, so it must be length number 12

in case the product is produced with a tolerance S - 0.5 = 16 + (0.76 x length number)

S = (24.5 - 16)/0.76 = 11,18 ; which can create the error that you would assume you require length number 11, which is wrong.  That's why we would always ask a picture of the receptacle, and measure up the panel thicknesses, so we can correctly determine the length number.