Hmmm, i dont see how that proves your point.
Question was, in case of the 1000 years, it clearly says, as per your reckoning. But in case of 50,000 years it does not!
Beside this, you agree مقدار and قدر can have identical meaning.
Also, In Arabic, it is not common to use the word مقدار for the length of a period.
Beside all these, there are Hadithes, as shown, that on Day of Resurrection, things happen fast, so that a year is like a moment of flame of fire.
Now, how logical it is to say, the Qaim cannot come and say, God caused this 50,000 years, to pass in a moment?
Don't you see, how this can be an example, that the Muslims argue with Qaim to reject Him? (The same way, other Ummah argued with their messengers?)