Maybe something to also consider in the calculations for Lead Acid vs LiFePo4 is charge efficiency.
Here is the conundrum - if you are able to feed back to grid you can basically pass everything you have back to the grid, i.e. 100% of solar production less internal conversion losses.
Now say you would like to limit the amount you feedback for whatever reason, i.e. you have a surplus you can throw at charging batteries and thus use the batteries at night.
With Lead Acid - the approximate charge efficiency is about 80-85% at best. With LiFePo4 it is around 95% from what I have read, plus it charges faster.
I.e. - with Lead Acid it makes more "sense" to rather push everything you have at the grid than to loose in charge inefficiencies, but it also does not really make sense for that investment to stand around and gather dust.
Thus: You have less energy losses with LiFePo4 in charging than with Lead Acid. And to me 10% is nothing to frown at.