I think it's fairly clear there that your nightime dose is too big if you're dropping that much.
One thing to discuss with the DSN is adding more morning dose and taking away some evening dose.
Are you eating a late, carb rich meal that is causing a pre-bed high,and if your dose has been based on that, could well be wrong. Are you doing both post and pre meal checking or not? A lot of T2s don't.
A lot of advice above is from others like myself who have been on DAFNE, or similar courses for T1, which is all about tailoring your dose to you specifically, so please bear in mind their perspective, but I think you would find it helpful to talk to a DAFNE trained DSN as well as I would not be entirely sure of my ground when talking about insulin doses for a T2.