Right it does not shut down your production, but your body will release less of it. Think about it if your body released the same amount in addition to the exogenous insulin than it would be IMPOSSIBLE to raise your blood glucose levels no matter how much you ate.
Yeah I believe as long as you keep your insulin dosage in the 10IU range and cycle it you should be fine.
On a side note I have been using 5IU of humalog only on training days PW. I put 8g creatine, BCAA's, glutamine, 40G protein, 50g carb matrix (mix of maltodextrin and fructose) I know fructose is not quick acting but the maltodextrin is. I also have gatorade powder which is pretty much pure dextrose and sucrose which I make an additional drink of.
I drink the protein/creatine/glutamine/carb drink immediately after injection, then eat an apple, a banana, boneless skinless chicken, and green beans after my shake. I drink the gatorade powder drink while eating this meal.
about 45 mins later I drink some grape juice (simple sugars) and eat another meal such as rice or potatoes (for my complex carbs) to get a good balance of fast and slow acting carbs.
I continue to keep a small container of honey nearby and glucose tablets. I check my blood sugar around the 2hr mark just to be safe. Usually it is around 130. People say humalog peaks at 2hrs but I disagree it hits HARD at the 30 min mark stays the same for another 30 mins then slowly goes down until the 4 hr mark.
Anyways is there anything I should change such as my carb sources? I try to have a good balance of fast and slow acting carbs and so far things have been good. I still get tired and a little light headed at the 30 min mark after injection but my sugar never goes below 90 and after that I feel fine and maintain 130 level for the next 3 hours.