Calculating measure for non-existent data

Apologies, my table 3 was incorrect. See below amended screenshot.

Explanation:

Table 1 is what the underlying data looks like.

For Table 2:

PriorMonthBalance is a measure calculated as: CALCULATE(SUM(Table1[Balance],PARALLELPERIOD(Table1[Date],-1,MONTH))

Month over month change is a measure calculated as:

SUM(Table1[Balance]) - PriorMonthBalance

Table 2 should show the change in balance from each account from Dec to Jan.

Account A Dec balance was 100 and Jan balance was 50 therefore, Month over month change = -50

Same idea for Account C.

The problem with Table 2 is it is missing Account B. Looking back to Table 1, Account B had a balance of 200 with no data point in Jan. How come the Month over month change measure is not showing -200 for account B in Table 2?

What I am expecting as an output is Table 3. It should show the month over month change for each account.