Table : Physical Attributes

Hi,

I need some DBA advice on this :-
I have a table whose physical attributes are as follows
PCT_FREE = 10
PCT_USED = NULL
PCT_INCREASE=NULL
FREELISTS=NULL
FREELIST_GROUPS=NULL

We are using Merge statement for DMLs on this tables. It is bit slow.
So we started using hints like parallel append etc. I am just wondering if I can modify the physical attributes of the table to improve the DML performance.

Cheers !