Possible issue here: 288 is linked from http://www.livejournal.com/manage/account/?changelevel=1 (the "I want to get rid of my ads" page) as a "here's what you'll lose if you switch to basic", and 114 is more general. Still, I think it's better not to duplicate information if possible. Hmm. /manage/account/downgrade.bml also links to 288, and 288 seems to be direct copypasta of that page.
As far as downgrading itself goes, what URL should be linked to? 114 links to http://www.livejournal.com/manage/payments/ (which redirects to /manage/account/, which if you're Plus is just a Paid account upsell). 288 links to http://www.livejournal.com/manage/account/downgrade.bml which seems to be the direct "downgrade me now!!" page. http://www.livejournal.com/manage/account/?changelevel=1 might even be a better page to link to as it gives all three options.