There is the possibility that it showing the balance less the fee? The two wallets in question both work, but differently and so they could show a different pre-calculated, spendable balance wrt to the forseen fees per the number of held utxo’s, they all individually cost the same to spend.
Also, just to clarify, you’re talking about zecwallet LIGHT, and not zecwallet fullnode, correct? (Its a reasonable assumption)
You could potentially try out the latest Ledger 
fork of zecwallet light which supports an initial server selection screen so you can open it, import the seed, and then set about generating new addresses, which will be the old addresses you are trying to get. Now, I haven’t tried it just yet, it got pushed only a few days ago. The old one (on desktop, not mobile, that’s a whole different thing) could open with a change to its config i.e. type in a good server in the file before it starts. BUT it was never updated to support the new base fee and zip317, hence it really probably wont transact. However, it should recovery your data and eventually(
) sync at least as a method to cross-check. Be sure to try to get them all regenerated before you start the sync, otherwise it will just compound the overall time it will take.
The thing with this (as well zingo pc) is it requires you to setup yarn. Yarn is enabled with corepack, which ships with NPM, and the easiest way to get that is with NVM. So,
1 install NVM,
2 use NVM to get the latest (lts) NPM (these first two are the medium article),
3 use NPM to install yarn (the corepak link),
4 enable corepack (the installation link, I know confusing!).
After that (also you need Rust 
), follow the normal installation instructions. I will try it out and let you know.
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Update: this doesn’t (immediately) compile in UB 24. I actually incurred the same issue with zingo-pc just yesterday after a dist-upgrade 
so I’ll boot an older version and try. More info here Discord