I agree; I think that rule conflict should be formally addressed since many existing GMRS radios are incapable of switching to NB. I think the FCC made an inadvertent error.
Let's see......
All of the current crop of bubble packs already operate in narrow mode on all 22 channels. FRS has been narrow only from day one in 1996. Some 22-channels had an option of running wide mode on the GMRS primaries but most are narrow only on all 22 channels.
Part 90 equipment has been required since around 1997 to include narrowband capability (2.5kHz max deviation) in addition to old school wideband (5kHz deviation). The receivers are also narrowed in addition to the transmitter deviation when operating in narrow mode. Such equipment would be denied Part 90 type acceptance if it didn't include narrowband capability. Included in this are Part 90/95 dual certified equipment. It is because of Part 90 being required to include narrowband capability that Part 90/95 dual certified equipment manufactured since 1997 already has narrowband capability.
My Kenwood NX-300 UHF handhelds have Part 90/95 dual certification and have narrow capability in analog mode. My Kenwood TKR-850 repeater (sold it several years ago) has Part 90/95 dual certification and is wide/narrow capable. I operated it in narrow mode on GMRS to keep adjacent channel splatter from bubble packs from bothering it on the upper FRS channels adjacent to the input. Several iCOM Part 90 handhelds also have Part 90/95 dual certification post-1997 and have wide/narrow capability. I owned a few Kenwood TK-370G and TK-3140 handhelds back then and all were part 90/95 dual certified and included narrowband capability. The list of examples goes on.
With the rules proposing to allow FRS to use higher power on the upper FRS channels, repeater owners operating their repeaters in wide mode may find the repeater input getting hammered by splatter from bubble pack on the upper FRS channels adjacent to the input. I've had this happen before with my repeaters when operating in wide mode. All adjacent channel splatter problems from bubble packs on adjacent FRS channels went away completely after switching my repeaters and handhelds to narrow mode. No loss of coverage was experienced. Narrowbanding works.
We've had narrowbanding for 20 years. Part 90 equipment including Part 90/95 dual certified equipment manufactured since 1997 has narrowband capability. To say that most GMRS equipment is incapable of narrowband operation isn't quite true. Maybe it's time for people to think about retiring their ancient Motorola Micor repeaters and pre-1997 Part 90 handhelds and mobiles. It's probably getting hard to get parts for them now.