strange compression results

hello all, just copped myself a 2008 231 gun metal grey, only thing is it's got 109000 miles, got it cheap £1300, in heindsight whish i spent a bit more, seems to drive spot on but thought i'd get a compression test at rotary revs which came up with strange results on front rotor 5.1 5.0 5.1 rear rotor 7.2 7.3 7.2 standardised to 250 rpm, the mechanic said he can't remember ever seeing a result like that but not to be overly bothered he suspects the engine is fine, does anyone know why the low front rotor rate might be?, cheers matt