I'd recommend importing the watching only addresses into electrum? I know you can definitely see the totals there...
If not there's probably an online wallet that'll do it for you. But it's more of a wallet functionality than a block explorer.
You are correct. I was annoyed that nobody noticed that it was not working properly and was then overthinking it.
Thanks for the advice, imported it into electrum and got all I needed.
Thanks,
Dave