Not a lawyer but basically based on the information you have given she will unlikely change the 50//50 arrangements legally.
Both of her reasons are irrelevant for a change.
What may change the arrangement is if the coparenting becomes hostile, but let's say she becomes hostile, they may award you 68% and her 32%.
Basically your best approach is to highlight this arrangement has been in place 18 months, that dad has relocated to continue arrangement, that it's in the best interest of the child for them to have a meaningful relationship with both parents.
Alex Xela