The ramp up of the business model of point of sale financier Afterpay may be proceeding well, though losses are also piling up.Afterpay Holdings' financial results for the half year to December 2016 put "underlying merchant sales" at approximately A$145 million, or more than 11 times sales (on the same "underlying" measure) across calendar 2015.Momentum is evident, with Nick Molnar, the managing director, putting the "current (post December 2016) annualised run-rate of underlying Afterpay merchant sales" at "in excess of $480 million."Other key growth metrics reiterate recent growth.The number of "integrated retail merchant clients" (the company's jargon) was 2000 at the end of December 2016, but surpassed "over 2,600 today," the firm said on Friday.Afterpay put its number of customers at around 350,000 at December 2016 and reached "over 450,000 today, growing at over 2,000 per day."The average loan tenor was less than 30 days, the firm said. The average order value was $150.All the cash flow from merchant and other fees of $6 million still won't pay the bills at an outfit in business barely 20 months and bent on fast growth.The EBITDA loss was $700,000 and the net loss $1.4 million.But merchant fees were $4.3 million in the second quarter of the first half, another indicator of the tempo at the company.In an idealised model sketched out in an investor presentation, Molnar projected a prospective return on equity of "greater than 30 per cent."