I found that the Ernie Ball 105 flat has some subdued growl that coordinates well with a set of settled in Fender flats, when the Fender 105 finally thumped out, but there was still life in the rest of the set. To me, yes, there is a slight difference in feel of the 100 compared to the 105, but I would not necessarily call the 100 "floppy." I would get the L set, 45-60-80-100, and set the E string the slightest bit higher so you can "dig in" more; and if it thumps out before the rest of the set, then get the Ernie Ball 105 to replace it, and lower the bridge saddle back down a hair. The strings are so close to each other in their characteristics that there should not be any, or hardly any, compensation difference.
By contrast, for a 105 E string on the standard 34 inch P-bass scale, I found the GHS Precision flat to be much darker, the Chromes to go from zing to thump, but no growl to match the rest of the Fender flats set, and La Bella "rounder" in tone.