FT drops fast, globulin+T does not. So TT can be higher than you think at times of low FT.
LH/FSH suppression is from Bio-T and estrogens. E2 [estradiol] is more repressive than T. Transdermal T has the highest potential for T–>E2, creams less so than gels applied to larger surface areas.
So you are not taking these factors into account.
LH has a short half live, FSH longer. You can test these to eval your conjecture.
The effects of FT and Bio-T may have a biological half life on the hypothalamus and there may be a component of LH/FSH suppression that lingers - many things are unknown.
Many do not get decent T levels with transdermal T and that problem is quite common with low thyroid function where absorption can be very poor.