If I understand your post correctly it sounds like you have originated 8.5 times as many loans as deposits within your AA. Moreover, your market share of the mortgage market is 6 times your market share for deposits and you are not funding your lending activity primarily from deposits, but rather from sales into the secondary market (in other words, you aren't taking funds out of your community and lending them elsewhere). The CRA examination manual instructs examiners to put lending performance into perspective by comparing market rank and market share for deposits to market rank and market share for loans.
The primary way an examiner puts the lending volume (number or dollar) into perspective is by comparing the bank’s deposit market rank and market share in an AA to its market rank and market share in that AA for each loan product (number or dollar, whichever is applicable).
Do you know your market rank as a provider of mortgages in your AA? That also could be a big help to demonstrate you not only are meeting the need for credit services in your market, you also are a leading provider of such credit. With the market share you quoted you probably are in the top 5% of mortgage lenders in your market. In other words, you are more than merely meeting the need for credit services you are a
leading provider of credit in your Assessment Area. Leadership is a factor in CRA ratings too.