Changes in Google caching?

We are noticing a significant difference in the amount of time it takes Google to cache and subsequently rank a new page.

Two months ago, 3 to 6 weeks was a fair estimate to cache status with a PageRank of 0/10 in Google. A quality page rank would arrive somewhere on order of 3 months later.

Now we are noticing a cache time of 6 to 10 weeks with a grey PageRank bar and quality rank on order of 4 months later. This is calculated off of existing pages with an exiting Page Rank of 5/10, and a quality text link pointing to relevant content.

Could it be that Google is sending people to the Sandbox for a longer period?

The only good advice is to consistently add quality content to your website. MSN seems to pick it up first and Google will appreciate it later.