If they have reduced your regular payments it should still finish as previously agreed. If they have given you a payment break this will be added back on at the end. It all depends on what has been specifically agreed --- your own IP should be able to clarify.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk