Sumif based on date range

[Skumby]

I have a Statement spreadsheet I am doing for my dad's business. I need an Aged Analysis at the bottom to highlight how long an invoice has been outstanding. There are three catagories, Current (under 29 days), 30 days, 60 days and 90 days and over. I need a formula that adds up the total column based on the invoice dates, but I need the 30 days formula to add the invoice amounts for dates between 30 days overdue and 59 days over due.

I currently have this formula, =SUMIF($A$9:$A$20,">"&TODAY()-30,$K$9:$K$20) but when I enter in three dummy invoices for the 27/07/16, 27/05/16 & 03/04/16 for $100.00 each my aged analysis is bring up $500.00.

[xor]

Is it like shown in the attached?

[Skumby]

Awesome, thank you so much!!!!