Hi Deano,
Are you:

-sleeping on a satin or silk pillow case? Cotton will 'wick' the hair causing it to dry out and break.

-using a charcoal shower filter? If you have hard water with minerals it can shorten the life of your unit. And maybe that's why you have to shampoo it twice--definitely should not be necessary.

Your shampoo is a good quality. But you're not washing the unit two times--- you shouldn't have to do repeat the shampooing. I think that's your problem. With a charcoal shower filter you'll find that your shampoo will clean more effectively and you won't have to do it twice. And use cold water instead of warm water. The shower filter will be good for your hair---and your skin.
Regards,
John