I'm trying to figure out what do here. I had a Volvo specialist shop do a leakdown test and these are the results:

Compression:
1)180 2)150 3)180 4)180

Leakdown:
1)15-25% 2)9% 3)8% 4)8%

Major symptom is blue smoke out exhaust at idle after engine is warmed-up. No blue smoke at start-up when engine cold. No blue smoke when accelerating except when driving 20mph and acceleration seems to clear out smoke. Blue smoke starts after 5 minutes of driving 15-25mph. No smoke on highway (that I can see).

I'm using about 1/2 qt oil every 500 miles. Driveway has a few drips from turbo, but most this burned while driving and not on ground.

Shop says probably piston ring worn and believes turbo isn't causing smoke. Turbo is new rebuild from Cherry Turbos installed in December.

I do know my head gasket is going out, although at the moment the leak repair additive I used is working. Head gasket leaked coolant in September and then later in February. No oil ever in coolant during any of this. Shop pressure checked coolant and it was good, no leaking.

Am I looking at an engine rebuild? Should I have shop remove head, test it, replace gasket and look at cylinder walls?
Just give up on this engine and car?... very frustrated as to how to proceed...!