I wouldn't bother. I had mine cert'd in 2008. I debated on getting it recertified when it was close to expiring, but never did. I don't plan on running any races where it'll be checked. I don't see why waiting a few years will jeopardize it's recertification when it was done previously.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax