No, you can't change the formatting of a line item depending on the version or any other dimensions.
What you can do, and this won't work for everyone, if you have just one or two line items that you're displaying on a report, is you can define a text line item that picks up the numeric line item and formats it according to some custom logic. If you have lots of line items you may even be able to use a line item subset to pick up all the line items you want to format, then define your text line item with that.
An alternative would be to multiply your percentage by 100 (so instead of Actual / Forecast, your formula would be Actual / Forecast * 100), then you could use a very basic number format for all three versions (no percentage sign and no currency symbol).
