My last print bureau used to list the volumes on the invoice. And my various pieces of software agree within a cubic mm. Of course that doesn't hold for all designs. I notice you're talking about Clan Mechs and I assume Omnis? Many of those are Chicken-walkers. Those tend to have both spindly arms and legs.
For me, I know what my audience will pay. The Warhammers and Marauders sold out in two days, so those were under-priced at $20 apiece. Or were they? I did a second, half-run for Warhammers and they took a month to sell out. I don't like sitting on inventory for even that long. The Rifleman, OTOH, had a run about 2/3 that of the initial Warhammer run. Three months later and they're still not sold out. Similar deal for the Archers, which took about six months to sell out. All were $20 per kit. So I might be able to hit $30, but that's pushing it (though I did see one pop up on Ebay for $55 once) and it's going to leave me sitting on stock for much longer.
Now, I know what you're thinking... Maybe the kits were no good? Yes, it's patting myself on the back, but I have a darn good reputation. You're welcome to ask after me (Justicar) on Lords of the Battlefield and The Mighty Ten-12 (Star Trek 1/2500) and see what people think. I'm pretty sure you'd be amazed if you saw my Warhammer: It's 26 pieces (in two inches tall) and has fully pose-able joints. Check that Photobucket link and you'll see parts breakdowns for some of them. About the only thing I didn't do was individual missiles, and I was sorely tempted to. This is the sort of kit that FUD was meant for, but the price is just too much. Well, in resin it's a multi-part kit. In FUD I would have had a half-dozen pre-posed versions.
That's why I started looking at going from 1/300 down to 1/450. I figured with 1" tall models I could hit $10 even with mark-up. With the new pricing, it's over $10 just to print it. I'd say it's back to the drawing board, but I'll be damned if I'm going to go back and re-design a model that was within their design tolerances. There comes a point when it's just not worth the hassle, and that's pretty much where we're headed.
All that said, I won't post any real sales information here. That's not the purpose of this thread. Sorry.