Hi I sure someone with more experience than me when it comes to give insulin, but one thing I've noticed you are not doing any other testing other than AMPS and PMPS
It's very important to do some testing during both those cycles to see how low he is dropping
If you work all day I can understand that you can't, maybe before you leave for work you can test him @+2 meaning 2 hours after you give the insulin ,
At night is it possible for you to get more tests in such as +3 meaning 3 hours after giving the insulin, then maybe @+5 or @+6 etc
On weekends you can test more often, you can fill in test times such as +4, +7 or +8 etc
The more data you collect to see how he is responding to the insulin the better we can help you. If you want take a look at my spread sheet just to get an idea