Help with adding lookup values to main table (ApplyMap + Set Analysis returning 0)

[LoKi_asterix]

Hi everyone,
I'm trying to adjust an amount in my main table by adding a value from a lookup file whenever a few key fields match. I've hit a wall though my Set Analysis expression keeps returning 0, and a normal Sum gives me a completely unexpected number.
Here is what I’m working with:

Here is what I’m working with:
My Tables:
• Lookup file: Date, Account Number, Contract Reference, AmountToAdd
• Main table: Date, Account Number, Contract Reference, AmountOriginal, AccountType (and a bunch of other fields)
What I need to happen:
I want to create a new field called AmountAdjusted. When Date, Account Number, and Contract Reference match between the two tables, it should add AmountOriginal + AmountToAdd. If there's no match, it should just keep AmountOriginal.
What I've tried in the script:

ApplyMap(
'MapAmountadjusted',
Trim([Contract Reference]) & '|' & Trim([Account Number]) & '|' & Num(Floor(Date)),
AmountOriginal
) AS AmountAdjusted

Where I'm stuck:
1. When I use this expression on the front end, I just get 0:qlik
Sum({$<Year={'$(vMaxYear)'}, %Date={'$(vMaxDate)'}, AccountType={'001','002'}>} AmountAdjusted)

2. If I just use Sum(AmountAdjusted) and manually filter the Year and Date in the app, I get a number, but it doesn't make sense compared to what I expect.
Am I going about the ApplyMap addition the wrong way, or is something off with my Set Analysis? Any pointers would be hugely appreciated!

[Chanty4u]

Hi.try this 

MapAmount:

Mapping LOAD

    Trim([Contract Reference]) & '|' &

    Trim([Account Number]) & '|' &

    Num(Floor(Date)) as Key,

    AmountToAdd

FROM LookupFile;

Main:

LOAD *,

    AmountOriginal +

    ApplyMap(

        'MapAmount',

        Trim([Contract Reference]) & '|' &

        Trim([Account Number]) & '|' &

        Num(Floor(Date)),

        0

    ) AS AmountAdjusted

FROM MainFile;

In front end 

Sum({

    $<

        Year={'$(vMaxYear)'},

        %Date={'$(vMaxDate)'},

        AccountType={'001','002'}

    >

} AmountAdjusted)