Hi @Anonymous ,
Do you want to transfer data from table1 to table2?
I've made a similar test:
1)table1:
ClearCollect(data1,{project:"project1",StartDate:Date(2020,3,3),DurationInDays:60,ClientBudget:10000},{project:"project2",StartDate:Date(2020,5,3),DurationInDays:90,ClientBudget:20000})

2)table2:
ClearCollect(data2,{project:"project1",Jan2020:0,Feb2020:0,Mar2020:0,Apr2020:0,May2020:0,June2020:0,July2020:0},{project:"project2",Jan2020:0,Feb2020:0,Mar2020:0,Apr2020:0,May2020:0,June2020:0,July2020:0})

3)use table1 to update table2:
ForAll(data1,
Patch(data2,LookUp(data2,project=data1[@project]),
{
Mar2020:If(3>=Month(StartDate)&&3<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0),
Apr2020:If(4>=Month(StartDate)&&4<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0),
May2020:If(5>=Month(StartDate)&&5<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0),
June2020:If(6>=Month(StartDate)&&6<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0),
July2020:If(7>=Month(StartDate)&&7<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0)
}
)
)
//I just use mar/apr/may/june/july as example, you could calculate other months like this. Just need to make a little change.
For example: Aug:
Jug2020:If(8>=Month(StartDate)&&8<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0)
Sep:
Sep2020:If(9>=Month(StartDate)&&9<=Month(DateAdd(StartDate,DurationInDays,Days)),ClientBudget/(DurationInDays/30),0)
,....
Best regards,