toseg, I believe what you are saying is correct. If you have an uncompensated baro VNAV system you cannot use the LNAV/VNAV DA outside the temperature limits. You can still use the baro VNAV for vertical guidance but you have to fly to the LNAV MDA (and apply temperature correction to each segment altitude including MDA). If you have compensated baro VNAV you can use the LNAV/VNAV DA but you must still apply temperature correction to each altitude including DA. Ref AIM 5-4-5 and AC 90-105A App B.4.2