I'm no Volvo expert, but I'll try to summarize what I've read on this and other Volvo forums. The most likely cause is the cam did move some while doing the T-belt. I believe the 00 model year is like mine in that the exhaust cam is the only one that has the varible timing, the intake is just the traditional "fixed" style. From what I read, if the exhaust cam does move, just moving it back does not somehow reset the VVI part of the system, and there is a procedure where you resync the flywheel with a tool and the cams. When I did my belt I was told that you had to follow a specific prep procedure by turning the engine to TDC going clockwise and then go past by 90 degrees, then back to TDC. Doing this apparently sets the VVI up so you don't have these issues. I did mine this way and the intake did move about 1 tooth during belt removal, and I just placed it back. Every thing came out fine. My exhaust cam stayed put!

Is the mechanic experienced with Volvo's? Since he is using all data, that might not be the case. I've not used all data, so can't speak from experience if it advises the set up process. You might ask how he did the job, and if things moved on him during the uninstall process.

Do you have the experience to remove the cam cover and turn the engine over by hand? If you do you might at least be able to verify if all the marks line up correctly. Since the mechanic stated everything aligned per all data, I'm guessing the marks will align, but you would be able to confirm this yourself, and if they don't then you are practically there! If they do align correctly then see the 1st paragraph, as to how it might have moved, but can't be reset just pushing it back.

Perhaps some of the other more experienced members can do a better job giving more concrete advice and explain the VVT if things move, can they be just "moved back". They might also advise if both the intake and exhaust cams have sensors that would report "advanced timing".

Good Luck,
Jerry
01 V70 T5a