I am trying to create a pattern of slots along a piece of steel. The slot has to be spaced at 3" intervals along the length, the number of slots has to increase when the total length of the panel changes.

The 3" gap is important, the start and end gap can be anything from 1.5" to 3" but must be the same on both ends.

In the attached file i seem to have most of these functions working, but the equation is not giving me equal gaps on the ends.....

What am i doing wrong?

Any idea's would be greatly appreciated

Why you have not used an equation for direction 2 also? Also you can simply use the up to reference options and there would have been no need to use equation.