Dayum!.......giving you/installing 2 different heater types.....sounds like Honda is bending over backwards. Not sure how Honda could change the coolant flow???? I cant say I understand the mechanical details but my understanding is that the coolant flow is controlled in some way. As far as the block heaters are concerned, they were supposed to remove the original block heater but didn't. I am glad they didn't. In my area many of the hotels have cycling vehicle plug in power receptacles. I am not sure how that would affect the interior warmer as it starts and stops every second or two though DEFA tells me that it shouldn't bother it.