header_rewrite time based Rules

Hi Guys.
with the great stuff in header_rewrite plugin there comes an issue which arises.
Header rewrite plugin can modify configurable options based upon the condition rules and logic we use inside it.
the feature am asking for is to add timing condition for those rules
example
cond %

{time} >1600 [AND]
cond %{time}

<2000
cond %

{time:day}

=6
....
.....
....
.... [L]
where day<=

{0,...6}

{Sunday...Saturday}

for example between 20:00 and 23:59 set these conditional rules
other than this timing set other rules
that would be handy like for instance during high traffic hours of the day no background fill should be applied
during late night and early morning hours full background fill would be applied
and during medium traffic hours (16:00<->20:00) set background fill not to exceed 20sec

much regards
Faysal Banna