my max attainable when i moved in here was very low, and i knew it wasnt right, the engineer changed my port in the cab and i went from 54Mbps to 80Mbps.
so its not always crosstalk that is the factor, unless hes verified that or tried to change you to another port.
besides that, the checker is supposed to update according to your max attainable.
the checker once said 80 for me like yours and a min of 64 on clean line, it now says a max of 76 and a low of 55 on a clean line, im connected at 71/20.