Might also look at Lucky Seafood in Oakland Chinatown. I've seen lobster there for $6.99 but also higher, like $8.99 while buying crabs. 99 Ranch might be a better bet since larger stores might/should have less fluctuation.
Yesterday at Ranch 99 Richmond there were some lobster out of the tank labeled fresh. One fairly big fellow was still moving and I was sorely tempted at $4.99 a pound. However, after last week's 2 1/4 pound feast I just said no.