My Income Model, page-250

your revenue/ predicted receipts and % growth are realistic - but you need to account for more expenses.
your figures are based on turnover increasing but costs staying fixed.
this is extremely unlikely - marketing costs and staffing costs especially are coing to increase.
Insurance costs (which i believe are lumped in with operating costs) will naturally increase in line with sales.

yes there will be better efficiencies in scaling up.
but costs not increasing is unrealistic.