I clicked training for Design, the discription says that u will get marketers +1 AND 10% sponsors income in next race.
Looked and only Marketers went up.
I assume what u wrote is a typo as what u wrote is wrong.
trainign design adds +1 on next years car & +1 design skill.
training commercial/marketing adds +1 on Marketers skill & 10% sponsors income for just the next race.