A did a little research on Google to find out if these Lenovo models use the same WiFi card, and sure enough they do. Both Lenovo 100e gen2 and N22/23 use the same Intel Dual Band Wireless-AC 7265 NGW WiFi chip. At least, based on search results this seems to be the case, you may also want to check physically on the Chromebooks.
So, if the APs and WiFi chipset is same, ideally you shouldn’t have the problem with the signal/coverage. The only other thing that could cause problem is the WiFi chip “Driver” on these two models of Chromebook.
I would recommend you to check if the drivers are same, if not, update/downgrade the driver on new Chromebooks to the version on the old ones which works and re-test.