LUD changed again and again!?

[will]

My I-140-RFE was received 7/18/2005, LUD changed 7/19, 7/21, after 50 days 9/7, after 2 weeks 9/23 and today again 9/26.
Status not changed! Any idea? Thanks

I140-RFE rec 7/18/2005 status changed in 'It takes between 150-180 days..'
I140-RFE LUD 7/19, 7/21, 9/7, 9/23, and again today 9/26
Same status!
Is it frequent to have so many LUD changes?
Good or bad sign? Thanks.