I think in this instance although it is an event that WILL happen I would notify an early warning so you can highlight the issue and discuss in a meeting what they want to do about it.
Alternatively you could notify a compensation event, and get them to agree assumptions under 61.6 that you should base the price upon - which if then there are price increases for something specific the difference could be assessed. The alternative is that you price now any price increase risk and if implemented this would then be your risk.