The only change they made to the LTFs since they were introduced is the gauge for the A went from .070 to .075. According to La Bella, this was done after too many people complained about the .070 rattling and buzzing in the standard nut slot that was too wide for it.
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No change otherwise (that I'm aware of) going from "Low Tension Flexible Flats" to "Low Tension Flats".
That .070 A string on TI flats is one of the reasons I'm interested in trying the La Bella LTFs.