However, in the latter case the hindrance TEM for a wreck(s) is cumulative for the in-hex hindrance [EX: +1 for Orchard and additional +1 for a Wreck(s)].Just +1.
D9.3 ...This TEM is applicable only if the unit can claim no other positive TEM, but is cumulative with any SMOKE/Hindrance DRM applicable to the firer.
In other words, the TEM is not cumulative with other TEMs. presumably this includes other AFV/wreck TEMs. The same goes for hindrances:
D9.4 AFV/WRECK LOS HINDRANCE: There is a +1 Hindrance DRM to a same-level LOS for firing through (not just into or out of) a hex containing one or more wrecks/AFV,