@David Constantine My understanding is that their status page is typically just pinging netsuite.com and tracking whether you can actually access the login page, not whether their service is actually up. Sadly, it's on you to track the actual uptime. If you submitted/documented with support tickets the downtime and it's outside of the agreed upon SLA (99.5%) you can contact your support rep and get 1 month of NetSuite free (per quarter).

Will this fly if "downtime" was actually 2 weeks of dreadful slowness?

Not per the SLA I would imagine, but feel free to try