If any of you are still paying attention to this thread - I am having a similar problem with the mobile model TK-5810H(G) K2 hardware version 3. The problem with using KPG-95DGN instead of KPG-95DG is that 'DGN restricts channel bandwidth to narrowband maximum deviation (2.5 kHz) on a channel to comply with FCC mandates applicable to Part 90 services (i.e. land mobile radio, first responder radios, etc.) that went into effect a decade ago.
Presumably, you are using the TK-5210 for either Amateur (Part 97) and GMRS (Part 95) Services (or both), which still use wideband maximum deviation (5 kHz). If you use that equipment frequently enough, have others told you that your 'audio is weak' or that you need to talk closer to the microphone, or some other indications that you are not at the same volume level others are on those systems?