Back off sets after a stall

[SS2016]

I stalled and got my bench up to 98.5kg for 5 sets of 3 (got 97.5kg for 3x5) and press up to 62.5kg 4 sets of 3 (got 61kg for 3x5) after 10-12 weeks of LP. This stall came about as I was stressed from work, sick with the flu, sleep deprived etc but, if those factors weren't present, I probably would have only progressed by another 5-7.5kg on each lift so I decided to deload and work my way back up.

I'm doing each exercise as weight x 3 x 5 with 1 back off set of 8 @~80-85% of work set weight.

Is the back off set necessary after a stall to ensure I'll progress past the weight that I stalled at?
Is the rep range correct (8s instead of 5s)?
Should I just stick with 3x5 and when I get stuck again, just switch to 3x3 and maybe include 1-2 back off sets?

Thanks

[autumnal]

If the external stressors were temporary and now are under control, I don't see why you can't go back to LP.

I usually do back-offs at 90% of 5RM, but I'm intensity-dependent that way. I only do 5 reps or less, so not sure about 8s. Are you looking for hypertrophy over strength?

Some posters here recommend 3x5, then 5x3, then 3x3 and back to 3x5.