Actually, if you see the Notes section, you'll see that the Literacy class feature (which everyone but barbarians gets) allows untrained Read checks. Take 10 to read anything normal, unless you have an Int penalty, in which case you can just read it slowly and still take 10.
To pull apart your example further, "I will meet you at dawn" is nowhere near a whole page (10 full-round actions). I'd reckon it at a tenth of a page for this purpose, so one round, two if you're reading slowly. (You know what, even then it's still too slow. Maybe I'll make it so you can reduce it to a standard action if it's short enough, a full round for reading slowly.)
I know I tend to overcomplicate things in my rules. But I like things to make sense. Decipher Script just... doesn't. There's no good measure for when something is simply readable by a literate character, and when it needs to be Deciphered. It's down to the DM's decision on whether she wants her players to read it/find someone who can read it, or have to Decipher it. As Rich Burlew said in his Diplomacy rewrite (although Diplomacy was much worse than Decipher Script), "I want tools to use in the game, not a blank check to do what I want. I can already do what I want."
Plus my rewrite lets it be used for things like codes and ciphers, although you could cherry-pick these ideas and add them to Decipher Script.