That's fine then. On 4wd cars different tyre sizes mess with the differentials n what not.
If ifs fwd then a wider tyre would be fine on the front (it'll help with more traction) and slightly narrower on the back is fine because it'd reduce the rolling resistance. Or vice-versa if its a RWD car.
Also, some people say since the weight of the engine is at the front, the front tyres should have a bit more sidewall to cope - i don't see a loss here because at the same time the car would take bumps better as well with that extra give in the wheels.
Hope this helps.
BOL