Than was predicted vs than were predicted

Hi. I’ve found this sentence from here: https://www.english-corpora.org/coca/

1. Indeed, there have been those who have said I've underplayed them, and the actual results in the real world have actually been worse in the last few years than were predicted.

And this is my sentence:

2. The prices are lower than was predicted.

Why in sentence 1 we can use “than were predicted” while in my example “The prices are lower than was predicted”, we have to stick to “than was predicted”?

Thank you.