I had to fit a replacement lowrider to my recumbent from the same manufacturer (I don't know why we're being cagey, it's clearly HPVelotechnik), after the original was damaged through general abuse. It was an absolute pig of a job, and required me to apply tension to keep things lined up while barakta inserted the suspension bolts. I wasn't sure if it was actually a tolerance issue, though, as the main problem was keeping the lowrider rack, the main rack and the two parts of the frame all lined up at the same time (and it's entirely possible that the bike's no longer straight, after tens of thousands of miles, including many train journeys and several crashes).
I think they've failed to apply the "if you can't make it perfect, make it adjustable" principle.
To their credit, I was impressed that I could simply email them, get a timely reply, make the appropriate bank tranafer, and have the part within a few days - rather than the recumbent industry standard of people failing to follow-up on things, requiring that you deal with them by phone and so on.