Recycling FD's
My take on it is that as it's a NPA there's no useful guidance to be gained from the FD's below minimums and we should be visual anyway with the runway. Depending on your company's procedures if the MCP is set to the Minimums prior to descending from the platform then we would get ALT ACQ and ALT HOLD and the guidance would then be indicating for you to level off which isn't very desirable.
By recycling them we are arming them again in the event we have to carry out a G/A.
What the poster above me is referring to is if you just switched them off. The guidance would be available all the way up until we either engage the A/P, select a different pitch mode or indeed we get ALT ACQ and then they will disappear completely.