Have you done recent basal testings for these periods of time?
My thoughts are that your corrections may be having to work against basal rates that are too low..
Other thoughts, is your correction factor given, the same as your 2nd? Maybe for example that say at 3pm you give a correction... And your factor rate may be 1 to 3bg.
Then when you give your 2nd at a different time your correction factor may be 1 to 2.6 so you getting wrong correction factors used. The thing is, you should be aiming to get down to target level at 5 hours... Not 3.5hrs.. Your pump will recommend more according to your acting time and offset times... These will also impact on when your pump thinks you need more, even when possibly you would have come down after 5hrs....
Think you need to do basal tests for times of highs..
Do correction tests at a bg level of 10. Allow first correction to run for full 5 hours.
You will be able to see during the first 5 hours just how long your insulin takes to work, and how long it lasts if your basals are tested first and are good.
If I get my basals right first, I will eat 2 custard creams without a bolus. I know without a bolus and if I am at home, then my levels will go up to 9/10ish within about 50 mins.... I then do a correction and see what happens, how quick, and how long it takes to get back to target level. If I come down to target level before 5 hours... Then I know for sure that at 5 hours I will be far too low..