I couldn't find in SS where it says to start with your 5rm? I thought you started at a weight where your form breaks down and go from there. (Haven't read the whole book tho, and have yet to do more than skim Practical Programming.)
In any event, according to kethnaabs summary of SS, a good idea is to start with a weight 5-15% less than your 5rm to allow some room for progression.
Guide to Novice Barbell Training, aka the Official RIPPETOE-STARTING STRENGTH FAQ - Bodybuilding.com Forums
If you're eating enough and getting enough rest, and start at a point using that 5-15% rule, I would think you'd have no problem exceeding your current 5rm soon enough. If you have perfect form at your current 5rm, maybe wait longer, maybe 3-5min, between sets? Then eat and sleep and progress from there? Seems a lot of guys (and girls) on the SS forum, who've got their form down and are putting up some pretty good numbers, wait up to 5 min between sets.
Actually, the SS forum would be a pretty good place to ask about SS. Some really impressive numbers and progression being put up by a lot of the members, and a lot of 'em really know their stuff.
I'm no expert, but that's my $0.02.
good luck