Many thanks img. The same dyno has gotten "normal" results for the other cars, though I see the point about the weather station (also 5% humidity isn't possible even here.) I'll talk to them tomorrow and see if they know what is going on. We don't have tons of dyno options out here...
08 E90 | Jet Black / Black | 6MT
Mods: RAC RG63 w/ Pirelli Corsa 255F/285R | Akrapovic Evo Exhaust | OEM Blacklines
Winter Setup: OEM 18s w/ Nokian Hakkapeliita R 245/40-18