I tried pasting a link, but it always went to the home page whether I used Safari or Firefox. Here is the link

'http://www.tsp.gov/faq/faq1.html#sub4

If this takes you to the home page instead of the FAQ, you can navigate to the FAQ by clicking on "Account Access", then "FAQ" which is close to the bottom of the page, then "General Questions About This Website". The FAQ about Quicken is the fourth one on the page.

Basically it states that it was both too expensive and too cumbersome to implement.