Hi,
Well I can only guess but here goes.

Voltage:
$98B1=39089=158V : 39089/158=247
$9B99=39833=162V : 39899/162=246
$9C80=40064=163V : 40064/163=246
So, it looks like there's ~246 "counts" to a volt but again, that's just an educated guess.

Or perhaps there's an offset to it making values above 32768 positive and values below negative. In that case it might look like this:
(39089-32768)/158=40
(39833-32768)/162=43
(40064-32768)/163=45
Nah, that's probably not it.

The current is a little more tricky, here's my initial thought.
$7F9E=32670=2A : (32768-32670) / 2 = 49
$7C9C=31900=8A : (32768-31900) / 8 = 108
$789B=30875=16A : (32768-30875) / 16 = 118
$839F=33695=-6A : (32768-33695) / 6 = 154 (-154)

Clearly the above doesn't add up at all so there's something else involved.

So it's all about sitting down with pen, paper and a calculator and try to reverse engineer the numbers, try to find something that matches all the readings you have. Or try to find the specification of the protocol...

/Henrik.