The way I do this with my own self-employed clients is to look at the last three years trading accounts and see if there is a pattern - gross and net profit percentages, turnover levels, and importantly profitability. You also need to take account of any upturns or downturns in trading that you have experienced over the last year or so, and build in some sensitivity for poor results. It is easier for your IP to take more money from you at the end of the year if it has been earned, rather than you struggle - but of course your creditors do have to be convinced that you are paying a fair contribution.
With my self-employed cases, I also allow a three month window for payments to be made, to take account of peaks and troughs in trading - so for instance someone assessed as being able to pay over £300 per month would be allowed to pay £900 in each quarter. I rarely find that clients need to avail of this provision, but it is there just in case - and I have dealt with a number of landscape gardeners who work all hours during the summer but have little work during December to February.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
To have me propose an IVA for you, please visit:
http://www.melaniegiles.com/ivaEnquiry.asp
See customer feedback at:
http://www.iva.com/iva_companies/IVA_Advice_Bureau.asp