Information about discretion

So my partner has got EU Settled status that was granted on 11 Apr 2019, and has passed his B1 English, and Life in the UK Tests. Been living in the UK since Jan 2014.

We started applying for his British Naturalisation and everything seems okay except for when we got to the part where we we did a calculation of the past 5 years and he has spent 519 out of the country which is higher than we thought. We did a lot of travelling in 2015/2016 to visit his family back home. We didn't think the days were going to be a problem since he already met all the EU Settlement scheme requirements for 5 years history. I know the limit for Naturalisation is 450 days for a section 6(1) application, but they have some level of discretion above that. What is the probability that they will apply discretion and approve this application?

Is it worth applying anyway now? (He can apply until 21 Oct 2020, and then he will have to wait until 14 Apr 2021 as he was outside the country from 21 Oct 2015 to 14 Apr 2016). So it will be a long wait otherwise.

Other details:
- Only been outside the country in the previous 2 years for 87 days, and 26 days outside for the past 1 year

Thanks so much. Really would like to hear people's opinion if we can apply or need to wait.

I assume you have already reviewed the AN guidance https://www.gov.uk/government/publicati ... n-guidance.
Bear in mind your partner already has Settled Status so a wait until April 2021 is not such an issue - the secure status will not change until then and the requirements for naturalisation change rarely as it comes under an Act of Parliament. Personally I would wait.
The nature of discretion is that you don't have a right to it - you are free to apply of course and try and make the case, it may work or it may not work. If your application is declined the fee is lost (apart from £80). Waiting eight months to submit a then straightforward application would be more preferable in my view.