Cumulative % in loan schedule

[GINMED]

Hi,

in my loan schedule I have calculated Interest payment with such function:

Interest_Monthly =

VAR _PV = [PV]

var _Rate = MAX('Lig'[Rate in period])

var _Period = MAX('Lig_Project'[Seq])

var _AllPeriod = CALCULATE(max(('Lig_Project'[Seq])),ALLSELECTED('Lig_Project'),VALUES('Lig_Project'[PL Nr.]))

return

IPMT(_Rate,_Period,_AllPeriod,_PV,0)

And after that I put it in second formula to getting correct calculation:

INTEREST =

var FirstPayment = CALCULATE(MIN(('Lig_Project'[Seq])),ALLSELECTED('Lig_Project'),VALUES('Lig_Project'[PL Nr.]))

var CurrentSequence = SELECTEDVALUE('Lig_Project'[Seq])

var CurrentPayment =-([Interest_Monthly])

RETURN

SWITCH(

CurrentSequence,

FirstPayment,[Interest_FIRST],

CurrentPayment

)

And how can I get correct cumulative INTEREST?

Please help me to find correct function to get cumulative INTEREST data.

There is my sample data.

Many thanks in advance.

WBR, GINMED

[lbendlin]

The link to the sample file is private. Please check.