it says that you had not played long enough to develop severe difficulties making the transition.
Out of curiosity, how big is your monitor and (if you don't mind me asking) what is your age?
Being able to mentally link a coolie hat position with respect to your cockpit position in 3D space is quite a bit different then using TrackIR and 'knowing' you are looking 135 degrees right and 45 degrees up when you really move your head just 30 degrees right and 25 degrees up
But it is not 1:1 tracking nor are you keeping your eyes ahead, so you are still translating the perceived view as you would with a hat switch. In fact I'd go as far to say keeping your eyes on the monitor while you turn your head lessons the immersion quite a bit.
Size of monitor is irrelevant to the operation of TIR. The only thing a big monitor does is allow you to still be looking at the monitor as you move your head enough to the side to get your game head turned around. Those with smaller monitors either have to have a real aggresive profile (so they don't have to move their head around too much) or they will be pointing their head far outside their monitor and peeking out of the corners of their eyes to see the display.