Challenge IPA?

ToxtethO'Grady

You should make them aware.

It will probably not change the overall budget as tax credits will change due to her income, child benefit won't. Her expenses may change with transport etc for work so there may be a bit of juggling with the budget to come up with the same surplus available. You've already managed a discussion around your expenses once it will not be too much different.
The OR may ask for a copy of a wage slip from your wife but it's up to her to give that, she's under no obligation to comply.
If the OR finds out there's a change in your household circumstances and you haven't made them aware, even if there's no real change to the money in your surplus, they can decide to investigate more thoroughly.

TheGardener

Once your IPA is set up then the OR is unlikely to contact you or ask for any further information. Although you have provided an SOA and figures have been agreed for various elements of your household spending, it isn't written in stone that you have to spend it that way. If your family decide to live very frugally then there is nothing stopping you spending what you have saved on a modest family holiday. Obviously if a the ORs attention was drawn to a growing savings account balance then that might not look great but there is normally no real follow up BUT in theory, the OR could ask for more info at any point up to your discharge date.

Technically, your partner has no obligation to the OR at all. The worst the OR can do is assume she pays 50% of the household expenses. However, if your partners income is lower then the OR will have apportioned more of the costs to you so if your partners income goes up then the OR may want to revisit the IPA...