Here's a link about moving to 4hr EASY:
https://babywhispererforums.com/index.php?topic=63161.0At this age the guidance A time is around 1hr 45 to 2hrs. Often when an increase is needed you will not see an improvement immediately, it takes LO a little while to adapt to the longer time and it may also be that 1hr 40 is still too short, try not to judge the results on just one nap or one day as it is a transitional phase towards the 4hr EASY and a different routine.
It isn't possible to make any clear recommendations from the EASY you posted as I can't see exactly how long the A time was, how long the nap was or when he woke from the nap. If you could record your times over the next few days that would be helpful, it is always advisable to record the exact times during routine changes or when there is a problem so that we can see what is happening. Along with the times it helps if you can add a short note of LOs mood or if a nap was resettled or if you tried but couldn't resettle etc.
As it is though I would say the first A time looks too short at 1hr 30 whilst the following A time might be much closer to 2hrs which might be giving a better nap - I can't see when he woke from the 11.15 nap, if it is 1pm where you've put in the E then that's a good nap. The next A time looks more like 1hr 30 again but again unclear if this is where you are getting shorter nap or longer nap. And then there is a super long A time before BT in the evening, looks like 3.30 - 6.15 (between the end of the nap and putting down for the CN) which is 2hr 45 plus you've had a couple of days refusing this nap so maybe he's gone right through to BT at 8.30/9pm making a 5hr A time. This very long A time towards the end of the day can cause lots of BT resistance due to OT and although LO tries to go to sleep he may be too OT to be able to relax properly for sleep.
I would suggest moving to 1hr 45 for a few days and then if naps have not lengthened moving to 2hrs A time. Also to ensure the last A time is not over long and put him to bed early if needed.
At 2hrs your routine might look something like this:
WU 7.00
E 7.00
A 2hr
S 9.00 - 10.30 (1hr 30)
E 10.30 (this is 3hr 30 from last E)
A 2hr
S 12.30 - 2.00 (1hr 30)
E 2.00
A 2hr
S 4.00 - 5.30 (1hr 30)
E 5.30
A 2hr
E 7pm (this is less than 3hrs but it is the BT feed right before night sleep)
BT 7.30
If one or more of the naps was short you would probably need to add in a CN towards the end of the day and move BT later so that the A times work.
Hope this helps