I am wondering if it is safe to operate Japanese 100w MV lamps on both US 100w CWA and HX H38/H44 MV ballasts? I understand that US 100w H38 MV lamps run at 130v 0.85a while Japanese 100w MV lamps run at 115v 1.0a. Should these differing electrical characteristics cause any harm to the Japanese MV lamp or the US ballast?

I dont think lower current can cause any harm at all. Only the lamp power and efficacy, hence the light output, would be lower, but no harm to the lamp at all...