I know how to calculate % change, but have run into a snag when the preceding
period had a negative value.

If last-period I had 5 and this period I have 10, I want 100%. (No problem.)
Likewise, if last-period I had 10 and this period I have 5, I want -50%
(again, no problem).

If however last-period I had -5 and this period I had 10, I _want_ 300%, but
am getting -300%.
Likewise, if last-period I had -5 and this period I have -10, I want -100%,
but am getting 100%.

Here is a table:
Prev Current Have Want Good?
5 10 100% 100% Y
5 -10 -300% -300% Y
10 5 -50% -50% Y
10 -5 -150% -150% Y
-10 5 -150% 150% N
-10 -5 -50% 50% N
-5 10 -300% 300% N
-5 -10 100% -100% N

I tried using an embedded formula to do this, however ran into fact I can
only nest 7-layers deep.

I'm thinking I'm just simply 'missing' something; something really simple.

If anyone can help, that'd be great.

Thanks