You can use them again without worrying on losing out.
Since the price of SBD dropped below 1 USD, the witnesses have updated their pricefeeds to signal no bias or a negative one.
This means you won't lose out by choosing 'Power Up 100%' for your posts.
( If you don't know what I mean check this post )
Also it's safe again to use the 'Convert to STEEM' function in the wallet.*
*In fact, you might get a little discount.