Will blue essence conversion making upgrading mastery worth it?

Currently sitting on quite a few mastery tokens that I can use to upgrade my champions mastery. However, it's 500 blue essence for mastery 6, and 600 for mastery 7. Roughly, this means that after the conversion, mastery 6 will cost 3250 and mastery 7 will cost 3900. However, I'm not sure if this will be how much the cost is after the conversion.

So my question is: How much will upgrading a mastery on a champion cost in blue essence after the conversion? If it's less than 3250 and 3900, then I'll just wait, but if it's more, I would rather take advantage of the system before the conversion hits.