The text can reasonably be interpreted multiple ways and the impact to gameplay is significant. We need a FAQ entry.
My interpretation is that the Spring Attack feat grants two benefits:
1) As a full action, you can move up to your speed and make a single melee attack or combat maneuver without provoking any attacks of opportunity from the target of your attack. You can move both before and after the attack, but you must move at least 10 feet before the attack, and the total distance that you move cannot be greater than your speed. You cannot use this ability to attack a foe that is adjacent to you at the start of your turn.
2) If you have the trick attack class feature, you can take your movement from trick attack at any time during a trick attack with a melee weapon (instead of only before), without provoking any attacks of opportunity from the target of your attack.
The limitations placed on the special full action granted by Spring Attack are not applied when you use trick attack because you are not using the special full attack action granted by Spring Attack.
"You can take your movement from trick attack at any time during a trick attack" means that you can move, take your attack, and move again. If it meant "before or after" it would have been better to simply say "before or after".
However, I also see your points. There is definitely room for argument.