For those that are having issues with editing Player Skills it's already been mentioned several times what you should do here are some posts you guys should checkout and see if it helps.
Read through these pages as there are tips to get >
LinkLinkChecked up to page 184 about people mentioning the Player Skills issue probably as far as you want to go.
From when i was trying to max out my character like at the beginning of a new game i usually wait until there are some progress points then i would edit the number higher that way the next time you level it up it would increase several levels.
It seems on certain missions or even certain areas you would get the ?? or even a random floating number, i found going somewhere else or not being on a mission/gig helps but the editor is one of those works sometimes and sometimes doesn't.
Same goes for editing your Credits which is why when you can edit your Credits set it to a high number 999999999 then go buy Weapons, Clothing, Cars.
I myself have only edited my relic points as of late and haven't used the trainer for anything else as my character is maxed out and can handle just about everything.
Honestly for the rest of the Player Skills i think i only needed to max out Shinobi and was able to do so by finding progression shards on enemys and by those air drops.