What year is used to determine the combined family max?
I retired a few years ago and was receiving the family max due to my disabled daughter and my wife's in child care benefit.
My wife filed at 62 this year to implement the combined family limit for a higher benefit.
SSA used the year I retired to determine the limit for the combined family max not 2017, the year the 2 maximums are first being combined.
I reviewed the ssa section https://secure.ssa.gov/poms.nsf/lnx/0300615770.
The applicable combined family maximum limit is determined by the year in which the maximums were first combined. So, it sounds like the 2017 limit would apply in your family's case.
Note, however, that the full limit is not always payable, even if the sums of the family maximums on your and your wife's accounts exceed the combined maximum limit. This would be true in your family's case since your wife filed for reduced benefits on her own record. The amount counted toward the family maximum is a person's full retirement age rate (PIA), not their reduced rate (https://secure.ssa.gov/apps10/poms.nsf/lnx/0300615756).