When routines change things can seem confusing. You'd need to continue for several days (or longer) to see what happens really.
You did say that there was a BT issue of her not going to sleep well which I think is indicating OT after a shortish nap and a long A time. Sometimes OT can result in the occasional really good nap or BT as it builds up until eventually LO crashes for a good long sleep, or non-resistant BT. Try not to get confused by the occasional time she went right to sleep at 7pm because if this was consistent I doubt you would have started the thread about the BT issue.
1hr 20 nap is better and more suitable for her age. If you can get it a bit longer then great. I would continue with what was suggested:
- W2S for 3-4 days, then hold off to see what happens
- if the nap doesn't extend properly another cycle of W2S (3-4 days again) and possibly an additional 10 min A time before nap 2
- if nap 2 is short (1hr) then reduce A time before BT. Adding to this I would suggest if the nap is extended you could increase the last A time to 2hr 45. If the nap extends significantly (1.5 - 2hr long) then I would follow that with a full A time of 3hrs.
- I would not in any case aim for a 4hr A time prior to BT.
- If she is screaming and crying at BT to a significant degree where she just can't calm down I suggest bringing her out of her room to help her calm. Perhaps stay in a dimly lit area but different room, have a cuddle and calm words, then try again.
Sleep begets sleep. It might seem that she is not tired at BT but I believe it is more likely she is too tired to relax properly for her night sleep. If she can nap better in the day she is more likely to go to bed easier and more calmly and be able to relax for her night sleep.
The process of increasing nap length, overcoming any OT build up and getting a consistent routine in place will likely take a week or two with the methods and times I've suggested. You can post updates and you go if you like