If the children are with each of between 40-60% of the time, then child support is calculated by taking what you would pay (at $48k) subtracted from what she would pay (at $65K). She should be paying you about 160 per month CS.
There is no reason to pay her cash, or to give up your share of her pension in exchange for "no support."
If it were me, I would prefer to live in the same town as my child's school, activities, sports, lessons, friends, etc. for the simple reason that as she grows older and is more independant she will walk home on her own, invite friends over to hang out or do homework, etc. and it feels much more like her life and home is with you, not that she is visiting from across town or from another town. But I am sure you have your reasons.
I would respond to your ex this way then:
"According to the Ontario Family Law Act, the amount of your pension that accumulated during marriage is part of the marital property and must be split equally between us. Furthermore, under provincial and federal legislation, the Child Support Guidelines are mandatory and would show that child support must be paid according to the difference between our incomes. For this year, that would mean that you would pay me $160 per month in child support.
Because the amount of child support is nominal, I am willing to agree to have no support payments as long as our respective incomes are within $15k per year. I will also sign off on any claims against your pension. These agreements from me, if you agree to mobility allowing me to live with our child within (xx km) of her current school, and her remaining in the current school district. However I will only do this in order to avoid legal fees for both of us, which would mean less money available for our child. If this issue must go to court, then this offer is off the table and I will seek the full amounts as determined by Ontario law."