Luiz, I can't understand why neither mine nor your explanation works here.
To the best of my knowledge, 'as much as/so much as' mean: "almost", just as you wrote, "practically', '' really", 'in effect'' as I suggested and even "in fact", mind you, the idea it refers to is rather just implied(by the speaker's behaviour, register, intonation) than expressed directly, which, as I see it, does not affect the meaning.
So you can easily rephrase your sentences as: Mom really told Jane.../In fact, the clerk accused the customer (even though he never did it directly).
Have a look at some more examples:
By running away he as much as admitted that he had taken the money.=almost admitted
You as much as promised you would help us.=in fact/in effect/really, you promised
Your friends as much as told me that I was a fool.=possibly by their behaviour (arguing, butting in etc)
Don't you agree with me?
And thank you for the question.