By Profit %

The first approach is by using the Profit %, it categorizes the flags as follows.

White flag, is the default flag and is always empty after running the operation
Red flag, is the group of referrals having last 30 days profit equal -100% (including zero clickers)
Orange flag, is the group of referrals having last 30 days profit equal -50% to -100%
Yellow flag, is the group of referrals having last 30 days profit equal 0 to -50%
Green flag, is the group of referrals having last 30 days profit equal 0 to +50%
Cyan flag, is the group of referrals having last 30 days profit equal +50% to +100%
Blue flag, is the group of referrals having last 30 days profit equal +100% to +200%
Purple flag, is the group of referrals having last 30 days profit equal +200% or above
Black flag, is the group of recycled referrals.

To enable this feature, from the top menu, select Tools > Options, select Referrals tab and in the Automatic Flags Assigning section set the By Profit % radio button, check the Run always after adding referrals data, click Reset Flags Descriptions then click OK.

IMPORTANT! The last 30 days profit is calculated whatever the referral since date is lower than 30 days or more, this is processed correctly by the software. For example, if a referral is referral since 15 days, his last 30 days profit is same as his last 15 days profit.