Firstly, great job, it sounds like your initial testing has gone really well and it’s great to hear that you took some of our advice on board.
As you say, retesting as much as possible over the next couple of weeks is really important. When you do this, it would be optimal if you try and keep as many of the variable the same as possible (i.e. same training session, same temperature, same kit etc.) to try and replicate the same sweat rate.
As for the result itself, it’s very plausible. Although, anecdotally you’ve suggested that you anticipated a higher result which always raises questions as we know that most athletes who think they’re ‘salty’ generally are.
Once you’ve pooled some repeat data and feel like you’ve landed on a score that you’re confident is at least valid via your at-home protocol we’d be happy to discuss the implications in my detail over email, simply reach out via hello@precisionhydration.com