I might be a little more colorful than GDE regarding the dealer who just wants to throw parts, on your dime, at a problem until it 1) goes away or 2) you get tired of them. ECM "lost programming" is the functional equivalent of saying XXX computer program won't run because your PC's CPU is fried; excuse me if the CPU is fried the PC won't run. Anyway:
1. "68031593AA for the boost pressure sensor" translates to they want to stick you for a new MAP sensor which you have already done twice so I doubt that is the problem and your sure don't want to throw a 3rd one one there at dealer price + who knows how much labor for a 15 min. max. job.
2. there has been at least one case of P0299 being a vacuum hose issue. See
viewtopic.php?f=5&t=61240 3. at least part of your problem may be related to the CCV and all that oil which could cause MAP problems notwithstanding MAP replacements. It's possible your CCV valve is bad (PN5114348AB) and letting too much oil to vent from the manifold into the intake system. Of course it's also possible that all that oil on the top of the engine is from a bad CCV seal (PN 5114347AA) or a bad CCV to air filter>turbo hose. I know the top of my engine has not oil. I'd suggest a degreasing with like GUNK (spray on warm engine and rinse off with water with emphasis on rinse not a heavy spray as you don't want water in electrical connections) then drive a bit to confirm source of engine top oil.
4. you might also run for a while with the boost pressure solenoid bypassed, after checking vacuum hoses, to see if that stops the problem. Bypass see
viewtopic.php?f=5&t=70602&p=757348&hilit=boost+solenoid#p757348 PN is 4606226AC
5. EGR can be cleaned see
viewtopic.php?f=5&t=59352&p=659410#p659410 and
viewtopic.php?f=5&t=62495 6. with all that oil while it's probably not your issue it wouldn't hurt to pull the CAC hoses (boost hoses) to clean and inspect for leaks. In the process pull the air filter to turbo hose and check for a split on the bottom just in front of the trubo (on reinstall make sure upper end touches MAF sensor before tightening clamp) and check the turbo impeller for play (slight fore/aft ok barely perceptible side to side ok, more is a problem)