Is it a right way to supernet/range in OSPF for the following network address?

area 0.0.0.x 10.128.0.0 255.255.255.0 

How 10.128.0.0 can have a subnet of 255.255.255.0, e.g. /24?

Is this a right thing to do?

I thought the right subnet should be 255.255.0.0, e.g. /16?

Am I correct on this?