The string your link took me to was discussing loading rounds from the magazine because loading directly into the chamber was causing a problem. They were still having trouble diferenciating a controlled round feed action from a pushfeed controlled round action. They never discussed the accuracy of a rifle changing with differences in feeding.
There are some who say the pushfeed actions are more accurate than the controlled round feed actions (with a claw extractor) as the claw pushed the round to one side of the chamber(a miniscule amount) which means every rounds is seated a tiny, tiny, tiny bit out of square with the chamber/bore. The difference is much too small to notice with the accuracy we're likely to get from a sporting rifle. Have you shot any groups after this improved session, loading the ammo singly? If not do so. It is possible something else changed that improved the rifles performance and it just happened at the right time! In the post you refered me to, 'controlled feed' refers to the time of rifle action involved, specifically the type extractor the action employeed. It has no referance to any change in accuracy from loading technique.. Something else affected the rifles accuracy and I don't know what it may have been. What other changes took place in the time between the rifles poor performance and it's good performance? Did you perhaps take the rifle down for cleaning? Change the load or reload a new batch of ammo? Remember, the devils in the details...