PvB

Can a turbo waste gate be fixed by welding? 135i (2008 model), 44k miles. Bought 4 weeks ago. On sale noticed a noise when throttle closed. Dealer (not BMW) investigated found problem with waste gate. Claimed they fixed it. No noise. 2 weeks later noticeable fluttering sound when throttle closed. Return to dealer. Waste gate problem found (they say). Taken to 're-conditioning centre'. They claim waste gate fixed without replacing turbo by welding it. Awaiting more details. Now drives fine. Sounds ok - very faint sound on closing. Questionable power in 3rd or 4th. Very high consumption - struggles to do 300 miles to a tank (53 litre, 14 gallon, average 25-30 mpg). Should I be concerned that this has been a quick fix left me with less power very high consumption? Is it worth getting a specialist to investigate it? A specialist who diagnosed it said the waste gate could not be repaired without replacing the turbo. My suspicion is the dealer dodged the cost of a new turbo. Any suggestions gratefully received!