According to the BHL that lisha doesn't warm up the dough that is not a raya.
Orchos rabbeinu brings that the chazon ish did not stop every eighteen.
The biur halacha is not sure if the Rosh is referring to standard dough, or only dough that actually became warm.
In any case, if you are mechalek between the lisha and aricha then the dough being worked with the poles (if that is the matzah bakery being referred to) is presumably part of the lisha, further narrowing the chashash of the Rosh to the point the matzah reaches the tables and onwards. From there it’s only a couple of minutes until the oven and a very short window for leftover pieces to become chametz “Miyad” ,and 22 or even 24 minutes total should really make little difference vs 18. The whole 18 minute shutting down (I’m not referring to running dough through the same point in the process 18 minutes after the dough first passed through that point, which would have a much stronger basis to be makpid) seems to be somewhat arbitrary, and while it is undoubtedly a nice hiddur, going over that doesn’t seem to deserve the huge tumult people would make of it....