Yes ! Heath streak has made a valuable point on field restrictions.
I would prefer this way.
first 5 over restriction in the start of the innings.(1-5 overs) next 5 the fielding captain can decide any time during the innings (but continious) *next 5 at the end on the inngs (46-50).
* in this scenario the batting side might wait for the last 5 overs to score the remaining runs which might turn out too late. ( this could be interesting).
