Sounds like ATI did what we've done to my subframe. Sawzalled off the old stuff, c-shaped metal notched to clear the lip, full radius weld. Now if that POR15 would get here I could paint it and re-install.
I thinkn $400 is a fair charge as what HMS does is reinforce the stock setup, not eliminate it all together and replace with a much improved fully anchored mount. Not the same job, therefore not the same price.
I'd like to see some pics if possible.

Oh, and rear control arms are next..just finished the "to order" list last night.