50% Freeza

He really is using half power. If he went above 50% shouldn’t he say was?

You do not need redundant statements when there's already another statement telling you what you need to know.

It could just be that Freeza was so far ahead of Goku that he wasn't able to accurately grasp how far behind he was. The KHH doing nothing confirmed that a) Goku was that far behind Freeza, and b) the fact that it did nothing to him means that he has plenty of power to spare.

It's possible that he powered up slightly to block the KHH but I don't believe it's necessary.