Cash Budgets BPP Question No 56

Hi John,
Need help with this question.
QUESTION
JP Co has budgeted that sales will be $300,100 in January 20X2, $501,500 in February, $150,000 in March
and $320,500 in April. Half of sales will be credit sales. 80% of receivables are expected to pay in the month
after sale, 15% in the second month after sale, while the remaining 5% are expected to be bad debts.
Receivables who pay in the month after sale can claim a 4% early settlement discount.
What level of sales receipts should be shown in the cash budget for March 20X2 (to the nearest $)?

ANSWER
$290,084
Receipts for March:
$
50% March sales for cash (50% × $150,000) 75,000
80% × February credit sales less 4% discount (50% × 80% × $501,500 × 96%) 192,576
15% × January credit sales (50% × 15% × $300,100) 22,508
290,084
Why is the book solution not including cash sales of Jan and Feb but including March cash sales?
My solution

Jan Feb Mar
Sales 300100 501500 150000
Cash sales 150050 250750 75000
Receipts from credit sales month after sale 115238.4 192576
Receipts from credit sales 2 months after sale 22507.5
Total 150050 365988.4 290083.5
Grand total 806121.9