Record loan settlements over the six months to December have contributed to very strong growth in first-half earnings for broker franchise operator Mortgage Choice.Mortgage Choice made a net profit of  $11 million in the six months to December - an increase of 46.4 per cent over the previous corresponding period.After adjusting for the sale of a mortgage aggregator subsidiary, LoanKit, and also for the accounting treatment of trailing commissions, Mortgage Choice reported cash earnings of $9 million - an increase of 14.7 per cent over the previous corresponding period.The value of loan settlements rose 18.8 per cent, from $4.4 billion in the six months to December 2012 to $5.3 billion in the latest half.Mortgage Choice chief executive Michael Russell said low interest rates, very competitive offers from lenders and positive sentiment towards the residential property market had fuelled demand.However, low interest rates were proving to be something of a mixed blessing, with borrowers taking advantage of the low rates to make additional payments on their loans. These prepayments contributed to a higher than normal run-off rate in the Mortgage Choice loan book. While settlements were up 18.8 per cent, the loan book grew by just 4.4 per cent.One consequence of this is that Mortgage Choice's income from trailing commissions, its biggest source of revenue, increased by just one per cent.Mortgage Choice chief financial officer Susan Mitchell said the slow growth in trailing commissions was also due to changes in commission arrangements with a couple of lenders.Upfront commission rates jumped sharply during the half. Russell said St George Bank, Macquarie Bank, AMP Bank, Westpac, Bankwest and several others lenders had increased their upfront commission rates.Russell said the group was making progress with its financial planning franchise, launched last year. It has opened 23 franchises and is on track to have 29 in operation by the end of the financial year.