So to clarify, holders of original bonds are locked at 300Mh now? Then if "upgraded" to new contract they get 3 for 1 split at 100Mh each plus bonus which is depending on how much mine is costing to run and expand etc.
The effective rate of original contract holders is 300MH/s which is being paid at 100MH/s per contract due to the 3:1 split. Whomever goes to the new contracts, will receive 1 new contract for each current contract they currently hold. EX: If you hold 100 contracts currently, you will receive 100 new contracts at 100MH/s + bonus. The bonus will be based upon the then available funds to pay it.