09 Ford Expy EL LTD 6R80 RWD 105300 miles

Problem Short Summary: Intermittent Ticking Noise (similar to lifter noise) That Goes Away After Hard Rev. Codes P0346+P0022 Present.

Long summary: First instance occured around 2 to 1.5 month ago, where it was first observed after I pulled up to my house and begin after I shifted into reverse as I was about to back into the garage. Second instance was last night. I plugged it in my Autel scanner and saw P0346 and P0130. I cleared the code, took it for a drive, attempted to recreate the noise, was successful the second time. Only P0346 came back. Went to my Trusted mechanic, was about to get the engine to make that noise after shifting into drive then reverse and revving the engine. Noise started when the engine went back to idle RPM range. Using a stethoscope narrowed issue down to driver side lifter area. Once he was done, I revved it again and noise was gone. Plugged in my Autel and P0346 and P0022 came back. Mechanic noted possible damaged cam phaser issue and is best to be brought to the dealer to inspect. I have drove in all manners, very conservative and smoothly, and also very aggressively with a lead foot. No lack of power was observed. Engine runs very smoothly for the most part. Haven't brought it to the dealer yet as I need the vehicle for work. Plan to do it in 2 weeks as I have break. Dealer wants $190 and a week to diagnose. Curious as to see if there are any 5.4L 3v specialists' insights and expert opinion in this matter. Oil is clean and level is good. 

P.S. And I wonder if it's a good idea to just get a remanufactured engine instead of doing a timing job? I see one with 7 yr warranty for just $3.5k, meanwhile timing job at dealer rates is gonna cost about $1500-2000 parts and labor.