Please forgive me. I am unfamiliar with the tag values for KISS III. However, no one else seems to be answering your question so here goes...
I will assume that KISS III counts more than just 2 through 6 and T through A? Well, if so, the answer is no--not exactly. Any count that counts more than just tens will make it progressively worse for counting Lucky Ladies. For example, Halves counts almost everything differently than Hi-Lo except 3, 4, 6, 8, T, and A. Because of this fact, I'd have to wait until a TC of +8 before betting LL. In other words, Hi-Lo of +7 is not a very efficient indicator for LL but it is better than any other system that has MORE tag values. The upper and lower sums of absolute value tags for Hi-Lo is 5.0 and 5.0. For Halves, they are 5.5 and 5.5. Therefore, Halves is worse--KISS III may be too?
The answer to your second question may also be no. It depends on how much of the "payback" is due to the "jackpot." Essentially, when you bet $25 against a max. payout of $5000, YOU ARE CHANGING SIMULATED EV. The sims are based on a specific set of payouts to include the jackpot. If the jackpot makes up a very negligable portion of the overall payback, then you can get away with it.
The second question IS NOT independent of the first question. The TC trigger point for which you should bet LL is dictated by a "payback" that exceeds 100.00%. If you lower the ratio for the jackpot's payout, you may also significantly decrease the payback % at what was previously the Trigger TC. Thus, you may actually RAISE the Trigger TC. For example, you may think that your trigger should be +8 but if the jackpot is now only 200:1, your positive EV Trigger TC may actually be +9 OR HIGHER!
--Halves