Interest Calculation Method for Company Loan

Dear experts,

We've just had a new company loan that will be executed in next payroll period.

But we can not find the interest calculation method that suits with this company loan. Does SAP provide any way so we can create new interest calculation method in addition to interest calculation method which exist (30/360,30/365,act/360,act/365,act/act) ?

Thank you in advance.

Best regards,

fr4nk1s