Oracle have little to lose
By going for a retrial - as one presumes SAP will be re-admitting criminal offences before a US jury, and therefore Oracle will be getting at least what the judge thinks in any event. Gambling a few million for a much larger return is good odds.
I can outline Oracles closing speech now:
Ladies and Gentlemen, SAP thinks that they should only have to pay a nominal amount for their systematic grand theft. I hope you the jury show these scumbags that theft is never profitable and stick it to them for the $1.7B that our expert recommends, and not the pissy $400mill that their expert thinks they should get away with. You complain that companies who steal get away with it, now is your chance to make it right....