Low on oil eh?
Hehe...that's a first
I was thinking the flux capacitor may have a glitch ; o)

Just kidding of course...

I would pay attention to the control handle and it's circuits and outputs.

Was that tech that came out a raymond tech?
From the description and response you got it doesn't sound like it to me.
There are specific tests that can be run from the maintenance menu that will monitor voltage outputs and should reveal any abnormal signaling from the drive system or handle.

That's the problem with a lot of techs.... if the problem doesn't just jump right out there they don't want to spend the additional time to troubleshoot it.
Ughhhh....