You only hold the dose for 3 days on increases.....Reductions are different, but like Wendy said, today's numbers are probably because his depot was "overfull" from the 2 units, so even though you reduced this morning, it's still having an effect on his BG
We don't usually do back to back reductions since the prior dose could still be effecting the numbers.
If you want to skip tonight, you'd drain the depot a little and you could shoot at your chosen time tomorrow (but you'd still be at 1.75) or you can stall for awhile longer and see if he comes up high enough to shoot a reduced dose tonight to keep some insulin in him