Like with many of these things in today’s world, I tend to err on the side of caution
50 euro is about what I’d expect to pay for mastering a track normally (not sure what a radio edit would add), so prices are not outrageous. On the other hand, if you are a label and think something is good enough to publish, would you not just get it done and out there and deduct the cost from any future revenue?
But, I haven’t dealt with this particular issue myself, not producing tracks, so hopefully one of our producing members can shed some more light on this one.