Not paying across the agreed percentage of overtime or not paying across a windfall could be another reason.
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
Not complying with all the terms in a IVA (your proposal) could give rise to failing it.
Regards, David Mond, Insolvency Practitioner for over 46 years. Personal Insolvency Practitioner of the year 2012, Personal Insolvency Practitioner of the year finalist 2013 & 2014 awarded by Insolvency & Rescue Magazine and 2015 finalist for Personal Insolvency Firm of the Year.