For a short time, on the EXACT same lighting schedule, you should not really have any problems- However, your plants are much too tall for shop lights alone and what I'd do is run shop lights up top and then hang the big ass CFLs down in among the plants. Flourescents of any sort need to be REALLY close to the canopy, but if your plants are very tall, side lighting is a necessity.
Try to just get your new light ASAP and IMVHO spring for a 600, because you shouldn't be running a 400 over plants that tall either unless you do the 'lollypop' or 'pistilwhipt' pruning on them so tht the canopy is effectively only about a foot deep.