The concern I could see with this would be that you raise your price for a few days - you get a few takers but not as many as you hoped, so you lower the price back down to the original levels. I'd be a little concerned that those who subscribed at the higher levels would not be happy paying a higher recurring monthly fee when they could now subscribe to the product at a cheaper rate.
Would you / did you just manage those users back down to the original payment levels for the future months payments ? Or leave them at the higher payment levels and manage on an adhoc basis should they raise issue with pricing levels.