Personally I wouldn't go below $420 if it is so trashed that you have to HWE it.
If it can be encaped I would do it for $350.
That being said, I really must admit that I have come to the conclusion (after ten years of doing lots of encap cleaning) that you really can't charge much less for encap cleaning, and make what I consider a decent margin. Put away the bullshit idea about cleaning 2,000 to 3,000 square feet an hour. That's total crap that clever VLM salesmen came up with, and it's NOT EVEN CLOSE TO BEING TRUE on a day in day out basis. Sure I have covered 3,000 square feet in an hour in a few isolated cases but more often then not commercial carpet is pretty dirty and you can't JOG over it like they do in some of these bogus staged demos on ytube. Very often I can extract commercial carpet with the Steamin Demons in less time then it would take to encap it. Even with a truckmount & RX-20 or one of Eric's new Zipper units HWE will not really take much longer. The only real cost savings of encap cleaning is COST OF CAPITAL. If you do mostly commercial a mini-van, steamin Demon and cimex and you are ready to roll for very little investment. However if you do lots of residential and have a truckmount then SCREW ENCAP and buy a Zipper instead of a CIMEX.
The biggest question to ask on these deals : Will you have the tables & chairs put away when I get here or will I be responsible for moving them ? That can double the time required for the job.