Hi & welcome!!!
I got a little confused - you got a reading a couple nights ago of 191, and that was before she started on insulin? So then the numbers you have on insulin are these:
AMPS 253 0.5u
+6 176
PMPS 303
Did I get that right? So you are worried because it seems like her numbers are higher now with the insulin than they were before the insulin? I don't think it's rebound though, you get rebound with either a low number (under about 50) or a steep drop, and I don't see either of those. My guess would just be that you are seeing some natural variation in the numbers, or it's a little reaction to the extra insulin she isn't used to, but not real rebound. She had some tests in the upper 200s earlier, so with meter variation the 303 isn't that high - she may be seeing numbers like that at other times, just not when you tested.
I would stick with this dose for a few days (lowering immediately if you get any readings under 50, and keep a 200 no-shoot level) and keep gathering data like you are.