If 200 ISO Kodak from the lab means you ran a roll of 200 color neg film through the camera that's a useless "test." Color neg has tremendous latitude especially for overexposure. You can overexposed the stuff four stops and still get great prints.

I've no suggestions about the streaking though. That does normally indicate over agitation but I've no idea why some would be fine then start showing problems with the same materials and methods.