411A -
The primary reason that tail anti-icing is missing from many large jets (and some smaller ones) is that during certification flight testing, either with flights behind a spray aircraft, or with various shapped blocks glued to the tail surfaces, no adverse flight difficulties were found.
With all due respect Sir, that's BS that was fed to you by Boeing probably. The 737 was 'certified' that way after Boeing 'showed' the FAA that with shapes on the tail.
I've related my experience with tail ice on the 737-200 on here before and let me tell you there
IS an adverse control problem with tail ice. I also commented on the Midway accident regarding probable [my word] tail ice being the primary cause. I submitted my first-hand experience with tail ice to the Board with no luck.
Suffice it to say, if the wings will ice up, then so will the tail !!!!!