Jim, do me a favour and rename one of your MandelbrotMix3 fromulae.
 
I've renamed your latest version to MandelbrotMix3a as I *also* use an allinone.frm file :-)
 
MandelbrotMix3 {; Jim Muth
z=p5, c=pixel,
a=real(p1), b=imag(p1), d=real(p2), f=imag(p2),
g=real(p3), h=imag(p3), j=real(p4), k=imag(p4):
z=(a*(z^b))+(d*(z^f))+(g*(z^h))+(j*(z^k))+c,
|z| <= 100
}
 
MandelbrotMix3a {; Jim Muth
z=real(p5), c=fn1(pixel), a=real(p1), b=imag(p1),
d=real(p2), f=imag(p2), g=real(p3), h=imag(p3),
j=real(p4), k=imag(p4), l=imag(p5)+100:
z=(a*(z^b))+(d*(z^f))+(g*(z^h))+(j*(z^k))+c,
|z| <=l }
 
Both of these you have called MandelbrotMix3
 
Best regards,
Chris Curnow