Breadboard Un-ending

Everything was going so well with the breadboard ends.  The mortises were wider than the tenons, I tuned the fit perfectly, I squared up the shoulder so there were no visible gaps.  So far so good.

I clamped on the breadboard ends before taking a 1/4" drill bit to mark the current location of the center of the holes.  I used my double square to measure 1/32" or so toward the shoulder to mark