You really need some guidance based on how your insulin works. What kind are you using?
Generally, we advise new diabetics not to shoot under 200 but to wait 20 minutes without feeding, test again and if the number is rising over 200 to then consider a shot. With some insulins like ProZinc, we would suggest lowering the dose. With Lantus or Levemir, the advice might be different - those insulins have doses based on midcycle numbers.
It may be that your numbers are higher now because he is bouncing from a low number before that preshot of 176. When they go lower than usual, their body can release extra glucose that artifically brings the number up.
We would be glad to guide you with dosing. We have insulin support groups and specific info based on how that insulin works.