Confused

I’ve filed for a motion to modify custody (for VERY good reasons and my attrny feels we have an excellent chance at getting what we want not only with the evidence we have against her but considereing the kids also want to come live with us primarily) and my x wife has been very hard to get along with, especially since we filed for this motion. Well, she just got an attorney and her attny contacted my attny and said that she is offering for a “trial” reversed custody schedule for the kids during the summer to see how the kids like it. Which means, now she will get them every other weekend and every other Tues or Thurs. and we will have them the majority of the time. My question is, why in your professional opinion would she agree to do this out of the blue, especially when she is being so difficult about everything (like not letting me get them when I was supposed to on father’s day)? Just a little confused. We have mediation orientation in July and still don’t know when the hearing date will be but we know it will be no earlier than September. Can I request that in this trial period, I will be primary caregiver and will not have to pay her child support for this time period? Any advice would be greatly appreciated.

Thanks. I guess that why I’m confused b/c she knows I’m a great dad and I spend a ton of time with my kids, however; she is a pathalogical liar and she’s probably told her attorney different. Oh well, it’ll just hurt her in the long run.