Actually, now looking at your routine you actually prob are having overtired issues and need shorter A times rather than longer. You mentioned in your first post that your A times are 1.5 hrs, but looking at your routines above, your goal A times are 2hrs 15mins (7am to 9:15, etc). In your actual routine, you had him awake for 3hrs - way too long for this age! At five months, I wouldn't go over 2 hrs A time max. The first A time actually is often a shorter one, you can even go shorter than 2hrs if he is showing sleepy signs.
Try to aim for this:
E: 7am
A: 7:15-8:45 (I'm assuming you do a wind-down 15mins?)
S: 9-11
E: 11
A: 11:15-12:45
S: 1-3
E: 3
A: 3:15-4:45
S: 5-5:30
A: 5:30-6:45
E: 6:45
S: 7 (or tweak the end here based on your normal bedtime routine)
Remember, if he wakes from a nap early, put him down early for the next nap, etc. Look at each EAS as one independent block of time, based on when he woke, kwim?