I was very carefully monitored by my PCP and neuro while taking gabapentin and had been upped to 4200mgs/day by my neuro at Hopkins.
Eventually I switched to Lyrica,but had been taking gabapentin & tramadol successfully to control pain and symptoms for over 6 years before switching.
Everyone's drug tolerances are different, and just because someone says 3200mg or 3600mg is way too much, is out of touch with the reality of treating PN successfully.
There are very few absolutes in this world and if one is willing to admit that - they will be traveling on a road to many possibilities of action.