Best to ask your dealer ...
s/he is the one you are going to have to deal with if there is a warranty issue, etc.
so you might as well start with getting their interpretation of this.
By that rule, anyone doing FMQing would never get any sewing done,
as the machine would be in for service more than it would be home to be used.
FYI I have the 820 and have put a lot more than 200,000 stitches on it ... way more!
And have never had any sort of a symbol as that show up.
It does tell me when it wants oil.
Ironically, I have come to know the sound difference and usually have added oil,
just a wee bit before the symbol shows up on the screen.
Again ... ask your dealer and get the right answer!