Question about turn length adjustment in lockstep

Thanks so much for any help: I am working on a 1v1 P2P game using lockstep.

I read that turn length time, normally 200ms in a lot of games, is supposed to change dynamically through the game, going up quickly for lag spikes and back down slowly to normal for best smoothness. I read the 1500 Archers article already. It simply says that the host sends out target frame rate and turn length to other clients, which sounds great, but doesn't UDP pose a problem then?

My question is: if I have the host of the game send a new turn length to the other client, how are they supposed to really know 100% for sure that they both started the new length at the same time? A packet might get dropped, a reply may not come back, a turn might not increment. Then only one client may be on the 'new' turn length right...this is about as bad as a desync isn't it? Also the turn start times which are normally lined up within ~15ms accuracy are completely out of whack (they are straight up using different turn lengths / turn start times at that point). I have a hard time imagining how it's possible. Thanks again