As I mentioned, one of the most important characteristics of a reasonably competent skate tech is that his results are consistent. Clearly the one you were using isn't.
Did you order the Berghman sharpening tool? If you spend $5-$10 on it, it might be worth the hassle. Though it might turn out that new style Matrix blades don't have high enough runners to be used with that tool (you COULD file the tool back, but it sounds like you are too hesitant to do that sort of mod), it's still a pretty small risk compared to the costs of machine sharpening, if you include both the cost of sharpening, and of reduced blade lifetime, especially if you have to drive to use the new sharpener, in which case you should include the costs of running a vehicle.
BTW, 15 sharpening lifetime isn't really enough. That wouldn't flatten your rocker unless:
1. Your tech failed to try to maintain the proper rocker profile. In theory, they should have recorded the original profile (by tracing or photocopying it), and tried to make sure that profile was maintained.
2. They were flattening your rocker in order that you wouldn't unintentionally hit your toe pick. Done "right" (by powered sharpening machine standards, for figure blades - though of course there are no real "standards" per se), 15 sharpenings should remove about 15*.003=.045 inches - less than 1/20" - probably not enough to cause that problem, even though, in my limited experience, Ultima blades allow less room then MK and Wilson blades, before the toe pick starts to interfere too much. Even if it did, a really good tech would trim the toe pick back a little instead of altering the rocker profile. That doesn't quite produce exactly the original blade shape - because freestyle toe picks are tilted forwards, which means trimming would shift the point at which your toepick touches the ice slightly back - but it would work pretty well.
I've wondered if there shouldn't be better solutions for the "masses". Last I checked (a few years pre-covid19), USFSA had about 100,000 members, though that includes the LTS people. I'm surprised that's isn't enough for people to create s simple jigs to do this in a fairly idiot proof manner. Tools like the Berghman or Pro-Filer aren't idiot proof - which I suppose is part of the fun, like any skill.
As I mentioned, a tech doesn't have to finish under all conditions. In particular, if he uses a relatively large grit sharpening wheel (which, BTW, probably won't create as sharp an edge), it turns out, based on a test with a microscope I did with the help of an expert tech, that there is essentially no sharpening burr - though the edge is pretty rough. One COULD skate on it - though that particular tech chooses to finish even under those conditions.
Unfortunately, your new tech doesn't have a fresh blade whose rocker profile he can record. He may not know what shape that particular blade "should" take. If you want a less flat rocker, or to re-emphasize what I was taught to call the "sweet spot" where the rocker curvature changes up front, you will have to tell him that. It's a shame YOU didn't record the original profile, that you could give him - assuming you didn't.
Oh well. It is an adventure.