Just looked at my last job in acrylic (essentially a repeat of the clamps I posted in Calling All Makers: Carbide Community Build Competition #6 starts now! ), and your numbers seem about right for a 1/8" tool for slotting. (90m/min surface speed, 1100mm/min travel, 375mm/min plunge)
That said, I ran a ramped entry for the plunge on contours (slot cutting parts from sheet), and left 0.1mm (radial) for finish cut so the finish would be done in a single pass with space for the chips to clear.
The last job with a lot of clearing (a LOT of clearing for the part size, pockets and edge. About 50cm^3/part removed on stock that started at about 120cm^3 at 10mm thick) ran about a dozen times without an issue. This was done at same speeds, but 40% tool engagement (1.25mm radial depth), climb, and axial depth of cut/stepdowns 1.5mm. I used a helical entry for the pockets. The strategy was trochoidal (Fusion/Inventor’s “adaptive clearing”). Vacuum chip removal.
I would really, really suggest using a square end tool for everything but a finish contour. A SHARP one. Heat and chip buildup are your enemy, and dull tools rub. Ball end tools can rub near the center and have issues with chip removal and the low surface speed near the center.
For heavy clearing or finish, I would suggest ALWAYS climb with acrylic. The cutting edge gets in to the material without rubbing. Conventional, especially on a light cut, tends to rub, heating the material and dulling the tool. There are sources that will say the result is cleaner with conventional, and it can be since, if the chips stick, they get swept by the next cutting edge. On the other hand, climbing gives a better finish surface, in general, and if set up properly with a sharp tool, the chips won’t stick. A light, but substantial, finish cut (5% to 10% radial engagement is where I tend to go) leaves a fine finish.