any shard that has its value stay the same as it is now, will be doubled at the source, except in places like bronzium.
This is confusing, but untrue. Shards farmed have the same value. If you are farming Piett your shard shop from RH Poe income is relatively the same.
BUT, if you have raw shards, like a toon sitting at 200/100, like a lot of people have, converting those after the change yields have the buying power.
Shards lose buying power, but you only have shards stored in unstarred chars or unspent ally points.