The sales guy lied to you. Anything that is diluted with that much water isn't going to last and shower gels aren't meant to last. They're supposed to moisturize the skin and with the added scent will provide a good base especially if you wear the same cologne. A quality shower gel will have a thicker aspect to it which will make it harder to completely wash off with water. Usually it's shower with the gel, apply the body lotion, then the cologne.