Toyota Repair: 02 Highlander Oil Burning Problems, control rings, toyota dealership

Question
Just purchased a 2002 Highlander Ltd. V6 AWD as a private sale. Had only 98,035 kms on it. Toyota dealership did a safety on it before I purchased and found nothing wrong.
Two days later, I notice blue smoke coming from the tailpipe on start-up. Only lasts for a few seconds, and only when its been sitting for a bit.
Checked dipstick, was dry, and had just had an oil change at 97,000.

Took it back to dealership, suspecting PCV issues, but here's what they said:
"started vehicle after sitting for a few hours and substantial amounts of blue smoke coming from tailpipe. Removed front (bank 2) valve cover and inspected for excess sludge, but found minimal sludge (may be washed off slightly since fresh oil is added much more frequently now) and no signs of pcv system clogging.
Removed spark plugs and inspected electrodes, found a lot of build up from burnt oil. Performed compression test and found cylinders reach 175 psi after 6 - 8 cycles (spec 142 to 213 psi) when engine was mildly warmed. Removed pcv valve and related hoses. Cleaned valve and inspected hoses for fresh oil; none found. Pcv valve is working normally and not clogged.
Suspect piston oil control rings may be gummed up/stuck and not controlling amount of oil drawn into cylinders as well as the valve guides/seals may be faulty. Without further engine disassembly it is difficult to pinpoint exactly which is the fault"

They mention the compression is good, but then they say the rings are bad? The other issue I have is that they removed the valve cover without the PCV in it to see if sludge was problem. Shouldn't you look under the valve cover with the PCV? Toyota has issued a "revised" valve cover for these highlanders. That tells me that the issue is not with just the PCV but also on the valve cover to which the PCV is mounted. Just don't want to be screwed around by these guys. We send off a case to Toyota regarding the issue, and are considering returning the vehicle to the crooked guy who sold it to us without telling us about this.

Any advice/help regarding the dealership's diagnosis?

Answer
Hello, I don't think it's piston ring problem because you stated that the smoke disappers soon after startup, this is typically a valve stem seal problem, the seals should be replaced. A piston ring oil control problem usually results in the exhaust emitting blue smoke almost all the time especially under acceleration.