Or maybe not at all.
The 425 PMPS is from the HC food, so the bounce isn't as bad as it looks. If you get those kind of lows again, don't break out the high carb food unless he goes below 40. On Lev, even 40s aren't an emergency, unless it results in hypo symptoms such as parking at the bowl or glassy-eyed, but that usually doesn't happen till below 40. You can usually get them stable by feeding something, not necessarily high carb, maybe medium carb, around 10% of calories from carbs on the food charts. I consider high carb to be the 18% stuff, like the grilled varieties. He surfed very well on the high carb food, but the problem comes in later because the high carb + the bounce = 400s.
His double digits today were the result of a good dose which has been steady for enough cycles to really do its job. Since you lowered the dose already though, you might as well stay at 1.25U and see how it goes maybe 4 or 5 days from now.