I interpret her wording to mean that she thinks she should have more money based on the allotment of time and perhaps stuff she does with them or buys.
FWIW, I have very, very serious money issues and I am the BS but would not in a million years consider asking Perv for money for things that she is asking you for, GaHurts. I am getting no frills, no extra, no alimony, I am basically cut off as my own person from him though he is upper middle class, he is paying the bare basic CS that our state deems appropriate.
I have too much pride that came back, I think and I also don't want to interact or be seen as bitter or whatever in any, way and so we go without. We simply don't do activities that cost money or it happened that electronic/technology things are his area anyway.
I completely understand your thoughts on your children having a phone, esp. if there is a difficult time between the two of you with communicating, as your kids age hopefully you can work more with them and not her in between...
And no, FWIW to have another opinion, I would worry that if you "threw money at her to shut her up", it wouldn't be the end of her asking. Our divorce decree has terminology in it regarding this area of money and also there is terminology that says something like "no other words or deal or situation will override this document." The CS money is in there based on what the state deems appropriate and that's that...it's as the others say, to go back to court and spend oodles to get it changed.
I also wouldn't want you to have a hard time with the legal system if you changed the amount aside from the rules determined.
One thing that we do also, is in regard to things for our daughter as she mentions that cost more-we save them for gifts and discuss it ahead of time so that neither parent is left out or the other made to feel worse or like a competition.
She reminds me of my mother and sister, who want more out of life than they have the monetary means to accumulate or do-instead of no for an answer or earning it themselves, they seek people as sources to fund their desires-whether it's travel or stuff, instead of "no", as I have, they find someone to do it for them-provide the money-and it often doesn't get paid back. (Both NPD) I don't want that for you.Ashland 13
A person is a person, no matter how small. -Dr. Suess