The default dates will be amended to the start date of the IVA and will, like the IVA itself, sit on your records for 6 years. Changes from default to settles or partially settled might help marginally, but will make little difference. Also you cannot make the creditors alter the status. In any event, while the IVA is sat there, whether marked current or completed, everything else will not make much difference.
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