Again, greatly depends on your zone and rep. I get 2-3 trip charges per week for my maintenance zone($0.50/mile). I don't request them on every WO but I do periodically to help justify the driving we do to cover the zone, as we can usually route WOs which helps ease the driving time.
As far as CYD justification, I've never been dinged for not having marked loads. On the REO side they want white boards showing "Bedroom 1 - 5 CYD" or whatever, but that doesn't take too long. Haven't had anyone ask me to do anything with cardboard cutouts. REO is at $32.50/CYD but P&P is still $40-$50/CYD. I do measure the trailer/dumpster and take pics of that when job is done, but I think that's always good practice no matter the national, to backup how much debris was removed.
FAS tried offering me a flat rate for ~$700 for a property. I showed them the math of what Safeguard would pay and it was around $1200 for the same job - not including the fact that SG had allowables for all the other work needing done on the property(tarp, dehumidifier, smoke/carbon, etc), which would have made it about a $2100 job in one trip. FAS wanted the debris, cleaning and yard done for $700, and then each item bid(which none were approved). I ran the math on Cyprexx and even they came in at $1100 for that same job(but again, rarely approvals on "extras", and even then it's a second trip).
Not familiar with AMS's pricing structure as I hate to spend a lot of time to fill out a huge vendor package prior to getting pricing.
BUT, bottom line, yes, it's good in the hands of the agent. It's good to be accountable to someone local that can see your job, and also shares in the benefit of you doing a good job(house sells faster, higher price, etc).