Yes, it does appear that they do.

How long until step child reaches emancipation age for your state?

She may be waiting until dad files HIS request to stop cs. 

Or does your state automatically stop cs without going back into court?

HCBMs are family courts' bread and butter. The courts and the lawyers are happy to keep collecting those fees. 

Not to knock your and your husband experience but not all court systems are biased toward BMs just because of their gender. They're biased towards the BM most likely because she has custody and the kids are with her. 
 

Corrupt family courts favor money ... throw money around, buy the best lawyers money can buy (said lawyers have clout with judges who can be bought too)

GOOD family courts favor the children. That's what they're supposed to do. Whoever has the children will typically be in favor. 
 

Men want favor in the courts then they need think of how they can effectively prove their case (vs settling for a defeat before they've even stepped into court) and/or to file for at least 50% custody. 

we dot DH a lawyer who responded in that timeframe and requested financial documents. It has been over a month and there has been no response from BM or her lawyer. I told DH to contact his lawyer and find out how long BM can take to get back to him, so he did and the lawyer said because BM filed the petition she can take as long as she wants to reply, "up to a year or longer" according to the lawyer. Seriously?! 
 

second opinion 

Also, she insisted CS should continue, but in our state, CS basically only continues if a child is so disabled they can't support themselves, which is not the case for either SS. 

Family courts here in the South almost always go for the BM regardless. Two examples.

The BM here decided she needed a "rehab" stay at some church facility in New Orleans. We go through the legal process, at HER request, to get custody of the kids. She heads off to NOLA. Paperwork gets to the judge's desk to sign and he "demands" tp speak with the mother of the children to make sure she understands what she's doing. Add to the mix, CPS was involved and stayed involved for over a year due to her neglect of the kids. BM could not, or would not speak to the judge so we lost another $4000. Kids stayed in ClanLand with the sister and what a crap show ensued. 

I was called to testify in a custody case. BM had a boyfriend who "got in the wrong bed" one night with her 10 year old daughter. The child was besides herself and the dad had to get her immediately. Guess what? Judge decided he'd tell BM the boyfriend could not sleep over anymore. Nothing changed except the dad lost a couple thousand dollars. 

So, yeah...courts DO favor the BMs.

One of those things callled a job.   We don't want that, do we.  The thought of the $ drying up. No CS is putting BM into a panic,  

'Time to hire a lawer and put a end to this craziness for good.  You should agree to pat a % of SK colllege cost.  If they maintain a certain grade, have access to there portholes. Ect. Payed directly to college.  And any exter money give. To SK is up to you.  If you get disrecepter all is called off.  
'Any way you cut it. BM is out of the equation.  CS is not a lifelong payment