Question: In Alchemy, the rules for what kinds of cards can replace a trashed card are governed by the following, somewhat ambiguous wording:

> 
> Adding coins to a cost doesn't affect [potion] being in the cost or
>  not. If [potion] was in the cost, it still is; if it wasn't, it still
>  isn't.
> 
> 
> 

The rules then present an example with Remodel card. However, the Remodel card says:

> 
> Gain a card costing *up to* two more . . .
> 
> 
> 

The Governor card wording is:

> 
> Gain a card costing exactly one (or two [if you're the player playing
>  the card]) more.
> 
> 
> 

So, for the player who played the Governor card, it is clear from the remodel example that a card costing exactly 2 coins must be replaced by a card costing exactly 4 coins with no potion.

However, what about a card costing exactly 2 coins and a potion? If trashed, must it be replaced with a card costing exactly 4 coins and a potion? Or could it also be replaced by a card costing exactly 4 coins (but with no potion)?

Answer: 
'Up to' means you can exchange a card with potion in the cost into a card that does or does not not have a potion in the cost, but you can **not** remodel a card with no potion in the cost into one that does. Remodel says "up to". You may Remodel a Golem into a Gold, or Remodel an Apothecary into a Golem. 

If the card says "exactly" like Governor, the card to be gained has to have the same number of potions in the cost, and the specified cost in coins. If you play Governor, you can trash University, and the only possible card you can get in exchange is Golem, as it's the only card that costs exactly 2 more than University.
Every card has two costs - its cost in coins, and its cost in potions. The total cost is the combination of the two. So cards like Governor that tell you to trash a card for a card costing "exactly 2 more" want the cost in coins to go up by two, and the cost in potions to be the same. Cards that talk about "up to" a certain cost may or may not include potions - Gold ($6) and Golem ($4+P) both cost less than Possession ($6+P), but neither costs more or less than the other. And if you trash a potion-cost card to something like Salvager or Forge, which explicitly mention "cost in coins", the potion effectively disappears.

So in your case, if you Governor a Scrying Pool ($2+P) you can get a Golem, but not a Scout ($4), but if you Remodeled it you could.