[question] what is the use of field 'rate' about phpip HOT 2 OPEN

The "rate" column was meant essentially to attribute an ownership rate to each of multiple owners, for instance to determine what to bill each owner, or what share of royalty goes to each owner. It is just informative and not used in any calculations. Some companies also want to track inventorship rates between multiple inventors, for instance for determining inventor bonuses.

Apparently the renewal system looks more adequate for your purposes, with some adaptation. Also note that the tasks have cost, fee and currency columns, so you could configure rules that produce a "collect license" task with given (fixed) values for those columns. Unfortunately the task rule system is not based on the actor roles.

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c. royalty of actor A can be different with actor B

Hello,
I would suggest in this to have a matter for each actor, because there is probably an agreement for each actor, with its own signature date and perhaps each own term.

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