I'm extremely frustrated by these changes as well. We have three Powerwall installations - before the update two were on "Cost Savings" and the third was on "Balanced".
It used to be under the Advanced Balanced/Cost Savings, when we hit peak in the late afternoon, the TEG would send all solar back to the grid and we would run exclusively off the Powerwalls. This was great because our peak time credits were high, and helped off-set our other expenses.
Now, in the Time-Based-Control, when we hit peak in the late afternoon, the TEG sends solar to our home first and only sends solar back to the grid if there's any excess. The Powerwalls are not used at all until after sundown. So, we are losing significant peak time credits that we were receiving under V3 of the app.
Any fixes for this?
FWIW - we have a second system that hasn't been touched since V4 came out, and it still runs exclusively off the Powerwalls during peak (but at no other part of the day) as it did on Advanced Cost Savings mode before V4.