They no longer have one called "Tow". Its called Wild, Mild and Hot now. I always tow on 'No Power" or "Mild". And watch temps. I seem to be find on mild with my trailer empty, but if I have anything significant in it I drop down a level.
I've got the latest update- and stock, mild, wild, and hot, are replaced with stock, tow, street, and performance.. the values of whatever name you select are the same, though..
why 'tow'? dunno.. maybe they were reaching for options, and that one fit and also matched names comparable tuners are using.. the concern for towing in above stock settings, is that a hellalotta torque is laid into the transmission, which resists it, as you would imagine a load would do, and gives you an opportunity to break something.. the lessor tunes (stock, tow) are better for this purpose..
edited to add: my preference, fwiw, is to roll out in stock setting- once the load is rolling, shift on the fly to either tow, or street.. preferably tow.. I seem to get better mileage on the higher settings, as counter-intuitive as that sounds..