Hi Adam
I am suprised that you do not have the 50% uplift provision! Did your creditors not modify your proposal at the creditors meeting? Have a look at your Chairman's Report to clarify this.
Given that you say that the overtime is a one-off, I would put 50% aside each month into a separate deposit account to pay over to creditors as a gesture of goodwill, but do take advice from your own IP who may have differing views.
As this is a one-off, you should not be required to increase your payments as a result of these extra earnings, as you will not be earning these sums at the time of your review, but your IP and your creditors will be appreciative of your gesture, and you can then also keep half the money for yourself.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk