It appears the bands in the center of the fasces are not clearly separated but slightly blurry. They would need to be fully struck and rounded in order to qualify as FB. I think you may have better chances submitting it to a different TPG, which may be more lenient and call it FB.
I found this article on NGCs web site. It doesn't say so explicitly, but it seems they only look at the center bands: https://www.ngccoin.com/coin-grading-guide/Grading-Mercury-Dimes.aspx "...Mercury dimes exhibiting fully split and raised central bands on the fasces are typically valued more highly than those on which the bands are either flat or merely separated without being raised"
I just read one somewhere that explained that the central bindings did not have to be rounded in what they referred to as McDonald Arches, but the split had to be continuous.
That is how I have learned it! Though I expect them to all be separated. tpgs grade them differently.
The only regret I have is not taking Brian's course as a 3-day version like the one in Denver last summer.