IPhone updates apps but iTunes does not

Question

Here's the scenario:
I recently got a new Macbook Pro to replace my previous model. I manually migrated the contents over from the old to the new, including apps, music and so on. I authorized iTunes on the new Mac with my AppleID, the same one in use previously and with the iPhone. Now when I check for app updates in iTunes I rarely get any results for new versions when the iPhone shows many more updates. Apps update fine on the iPhone - for apps installed on the iPhone, of course - but iTunes doesn't really show updates (1 out of 10 at most). It's rather frustrating given not all apps I've purchased are currently sitting on my iPhone, meaning apps in the iTunes library/on the Mac are not getting updated.
Is there any way to fix this behaviour so that iTunes will reliably see app updates and download them accordingly?
- MacBook Pro 8,2 (2.0GHz quad core i7), Mac OS X 10.6.7, iTunes 10.2.x and 10.3.x.
- iPhone 3G, iOS 4.21
One step I've not yet taken that I am about to do is add all apps from the library to the iPhone in hopes that kickstarts things updating in iTunes but I'm not hopeful that will fix updates.

Answer 1

Update:
In what I felt to be an overly drastic move I one-by-one removed all apps from my iTunes library and downloaded each one again in hopes of ensuring there was no Apple ID issue. It took a couple days between doing that and app updates actually showing up but now iTunes is reporting updated apps in the sidebar but says there are no updates when you click the Check for Updates link.
Meanwhile, the Appe Store app on the iPhone reports software updates and grabs them fine. So obviously this issue is still in place. *** Apple?