The spherical correction was weakened by half a dioptre, leaving the cylindrical correction unchanged. So for my bad eye, the computer prescription's SPH is -4.75 instead of -5.25. This roughly agrees with the calculator at http://www.computerglassesrx.com/

The PD for near vision is only slightly smaller than for distance vision: 60mm instead of 63mm for me, less than 5% reduction. I doubt it is all that important since I've been using distance vision glasses to read with for decades, but it is a fact that you have to go a little bit cross-eyed to properly focus on something close to you. I think it might help a bit for looking at very small objects just a few inches away, but ditching the glasses entirely works even better for me when I need to read eg. markings on a 4mm IC.

I asked for this as a reglaze and they called it a "Snooker lens" even though it was for a regular frame

Almost ungooglable, but I get the concept