Without doubt, you can solve this without using the Manual Profile option to set a custom fan curve - in fact, doing that alone would not solve your issue.
Your issue is a different fan header configuration option called the MODE. Unfortunately, your mobo manual does not even talk about that or show you where, but I'm sure it is there. See your manual, p. 2-1 and on. To get into BIOS Setup, reboot your machine and immediately hold down the "Del" key. Don't just tap it - hold it down until the opening screen of BIOS Setup appears. On the EZ Mode screen at bottom centre click on the QFan Control box. From here on your mobo has no info or pics. You will find that there are places to choose WHICH fan header on your mobo you are...