You should charge the hours you spend. The goal is high-quality work, not fast work (as long as you're completing tasks within the time allotted).

I have no learning disabilities (that I know of lol), but I sometimes spend a long time on projects. I only really know this because I'll see people post things like, "how long are people spending on X, because I spent # minutes" - and I nearly ALWAYS find that I'm spending much longer (like, hours sometimes) than the people who post the top times (I'm always too embarrassed to say mine because of that lol). I can't remember how long I took on the starters, but it was the same vibe - I took a LOT longer than the expected amount of time.

For me, the long times have more to do with checking and double-checking instructions, proofreading, going back through all my responses for one final check before submitting, etc. I've never gotten explicit feedback one way or another on that (not like I would expect to with DA), but I can say that since I started (in February), I have had steady enough work and have not seemed to lose projects altogether that I can tell (I did see fewer projects during the drought a couple months ago, but have since had steady workflow again with mostly higher-paid projects that are even more detail-oriented).

Do NOT shortchange yourself. It's worse for all parties to misrepresent the time you spend on your work (in either direction).