Whats the point of consent and asking permission if you get lied to

It is the case that girls successfully 'mask' better than boys, and so often aren't diagnosed until much older.

Autism is more prevalent in boys than girls, which is another reason why it might not be identified in girls.

None of it is easy, and it is very common for ND students to remark that people don't mean what they say, or say what they mean. Whether or not she is ND, OP shares that same confusion.

It's simply far too difficult to cover all eventualities-like being psychic and knowing you'd order two meals. Did you eat them both? Maybe she was more upset about potential food waste than the cost?

I don’t think either person was wrong really, there is communication problems and I agree that the friend is also probably ND if she mentioned the extra food x 2.
Both of their decisions and reactions make sense in a ND conversation.
I hope you can both put it behind you. Pay for lunch next time if it won’t leave you penniless, if you can’t afford it then I would have a conversation with your friend about it, hopefully you can both move on.

Oh, so you don't take everything literally?

It'd be a very strange fish that could read and type!

It is considered a useful social lubricant to NOT demand of others that they spell it out (or risk deliberate misapprehension by a determined literalist.)
Sometimes we speak in euphemism or circumlocution for reasons of embarrassment, trepidation, or any other kind of reluctance, and unless lives depend on it, we generally endeavour not to insist on an explicit exposition, but swiftly comprehend what is being said to us, out of kindness (or friendly affection, of course)

A person might be reluctant to tell her guest that she should limit what she selects as her meal, for reasons anyone could easily imagine, as it may embarrass one or both of them.
So the pleasant and grateful guest knows not to stick to the letter of what’s said, as this treat has been repeated weekly for a long time and she knows it ought to be at her expense, for once.
Similarly, if she made faint preparations to pay once or twice, but was assured it’s not necessary, she knows of course that her friend is hardly going to come out and admit that yes, paying would be a very good idea.
Her friend’s way may not be her own way of conversing (despite showing evidence of being at ease with elision and abstraction, in a very long ‘debate’) but she’ll gauge whether this is the perfect time to ignore what her friend says and just insist, by asking herself whether or not being deliberately obtuse just at that moment benefits her materially.

Not going to write much, as I don't want to derail an already prolonged thread. But, I'm just calling you out for your 'lighthearted remark about MH'. Just as I would be for a 'lighthearted remark about racism' or 'lighthearted homophobic comments'.

I have Dissociative Identity Disorder. Look it up and learn something. There's nothing lighthearted about severe childhood abuse and a lifelong disorder that leaves me wanting to kill myself. (I have MH support, so don't worry).