I repeat, the flow in the flowline is not critical. It is the flow through the valve that is critical.
And no, there is no requirement to make the pressure drop across a choke valve always in the critical zone, but if you don't then back pressure from the manifold would impact on flow.
Perhaps if you gave some examples or numbers or something then we could see where you're coming from.
At the start of a filed, especially say a gas field, the flow might start off critical in a valve ( say 300 bar to 50), but then as time goes on and the FWHP dies, then you could end up at say 80 / 50 and then an increase in pressure of the manifold starts backing the well out.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.