DHCP vs DNS Resolution

So I just switched to Fios and have been configuring the router.  I have been setting static DHCP reservations, so certain hosts will always respond via name and IP.   The hosts eventually get their static IP, but the hostnames that I've entered do not seem to be put into DNS.  It seems the original hostname of the device sticks.

To resolve this, I've had to create additional DNS for the same IP.   Seems a bit redundant to have to reserve a hostname/IP and then create the DNS for the same reservation.  Shouldn't it all happen with DHCP?