Many of us did --- you will be unlikely to be able to increase the allowance made by your IP, so will have to find any increase from savings elsewhere. Also it will be up to your supplier as to whether they would accept you on a new contract.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014
Sharing from experiences of dealing with debt
The greatness of a man is not in how much wealth he acquires, but in his integrity and his ability to affect those around him positively.
Bob Marley. http://kallis3.blogs.iva.co.uk
I upgraded mine in May, I was a bit nervous but after googling it (a lot!) it seemed if I upgraded with them directly the decision was made on the last 3 months account management. It seemed like going into somewhere like carphone warehouse wasn't good idea as the indication was their advises end the contract and start a new one for sales, rather than just upgrading. I did it online with my network and had no issues relating to my IVA, just their shoddy lack of notifications.