50nm before Kidli? RT Failure?

[Oxford1G]

1/ When flying out of MAN, we are frequently asked what level we can make 50nm before kidli and BIG? Just for general information why? What are the implications of informing you we are able to make FL270, or FL290? I only ask because the heavy jet that i fly lacks the performance of newer aircraft

Thanks

2/ -RT-Failure- If we were flight planned for FL330 south bound, and due to our heavy weight, or ATC reasons were at FL 310, at what point would you expect us to climb to FL330? at all, or when our flight plan says so? What from ATC's point of view would be the best course of action?

Thanks