Nav Log improvement proposal

Right now the more annoying thing in the Navlog is that you can't change anything!You can't change the cruise altitude without reloading the complete flight plan.Since i use the AS estimations for cruise wind for my planning, i would like it to remake its calculations without requiring to reload the FP, just by entering the new cruise altitude.And since we are at it: if i load a flight plan, while it let me choose the cruise speed, it doesn't let me modify the cruise altitude he reads from the FP.Also an option to update the calculations with new metars would be nice.My 2 cents :)