Add aggregated target and aggregated running actuals (from two different tables) into one visual

Dear all, I am currently creating a 'Line and Stacked column chart' visual, with the below data (sample) from [Target table] and [Actual table] accordingly, please see the below screenshot for detail. I have created a calculated measure in [Acutal table] for calculating the 'Aggregated Actual Sales', I used the [Sales Month] as the visual's X-axis and [Aggreated Actual Sales] as the Column Y-axis, when I dropped the [Aggregated Sales Target] to the visual's line Y-axis, it doesn't show the aggregated sales target value by month but the sum up value (in the below example, it constantly shows 400 for Jan/Feb/Mar, instead of 100-Jan/200-Feb/400-Mar), I feel that the issue is sth to do with the Visual X-axis, as I am choosing the [Sales Month] from the [Actual table], but I couldn't figure out how to actually resolve this, to achieve the ideal visual outlook, please help, thank you.