Shampoo A is a very mild shampoo not as mild as shampoo B bust still mild, it does not have enough cleansing power to clean up your scalp if you have dried up sweat, air pollution or product residue on your scalp. If this residue is not removed, glands on your scalp may clog up and start overproducing oil (kind of like when you get a pimple or blackheads on your skin). You may use a stronger cleaning agent (either a sulfate or a different anionic surfactant like c-14-16 olefin sulfonate to clarify your scalp. If you have a sensitive scalp then swap the olive oil for grape seed oil and also use less oil altogether. And lastly, we cant rule out the chance that you're allergic to any ingredients inside the product in which case you should stop using the shampoo altogether and return to a commercial product that is free from Blacklisted ingredients. This should be your last resort.