spamassasin custom rules

I have a lot of custom rules in 'local.cf' like these:

Code:header LOCAL_DEMONSTRATION1_FROM From =~ /user1/i
score LOCAL_DEMONSTRATION1_FROM 20
header LOCAL_DEMONSTRATION2_FROM From =~ /user2/i
score LOCAL_DEMONSTRATION2_FROM 20
header LOCAL_DEMONSTRATION3_FROM From =~ /user3/i
score LOCAL_DEMONSTRATION3_FROM 20would it be better to write it like:

Code:header LOCAL_DEMONSTRATION_FROM From =~ /user1|user2|user3/i
score LOCAL_DEMONSTRATION_FROM 20given that From cannot contain several addresses?
is there any way to make it faster?
as it is, it takes about 3 seconds per message to score it, is that abnormal?

thanks.