Will suppplmental T5HO lighting during flowering cause any stress?

Here's the story, I vegged with T5HO's and moved to a 400w HPS. I'm about 3 weeks into flowering and wanted more side lighting. Can I start incorporating my T5HO into my 12/12 schedule or would that throw off the plant since I'm already 3 weeks into flower?

Also I only have 6500k bulbs for the T5's so I'm not sure a sudden source of blue light may or may-not cause stress.

Thanks!

I probably shouldn't answer for lack of knowledge but wouldn't the simple solution be to use them and just get flowering bulbs? I got 2 replacements for 14$ at HTGSupply.com

Either way, the plants would love the extra light. No stress for the plants at all.

I'm afraid the extra blue light would bring on the veg hormones. Trying not to hermie as these seeds are from another suspected hermie- but they lookin great now!