Thank you both for the responses. So it does seem that the differences in opcodes made a difference, that's good to know, .I probably should have tried that in the first place!

One further question: if I wanted to manipulate this to play in a different key (I understand how to modify the  table to get different scales etc.), one way I found that worked was to modify this line:

aSig  wgpluck2  0.98, 0.2, cpsmidinn(iNote+iDtn), iPlk, 0.06

to:

aSig  wgpluck2  0.98, 0.2, cpsmidinn(iNote+2+iDtn), iPlk, 0.06
which alters the pitch up 2 semi-tones.

However to dynamically switch it between several keys in the score I tried using a parameter for ex.:

aSig  wgpluck2  0.98, 0.2, cpsmidinn(iNote+p4+iDtn), iPlk, 0.06

but that doesn't seem to work. I'm not sure why the parameter solution doesn't work as it does in many other circumstances. 

I know I could just make different instr, modify the trigger and call them as needed but is there an obvious solution to modifying instr 2 that's perhaps a little more elegant or less cumbersome that comes to mind?I have tried methods like adding:

iTrnsp = p4
aSig  wgpluck2  0.98, 0.2, cpsmidinn(iNote+iTrnsp+iDtn), iPlk, 0.06

and kTrnsp etc. but they don't seem to work either. 

Csound mailing list
Csound@listserv.heanet.ie
https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
Send bugs reports to
        https://github.com/csound/csound/issues
Discussions of bugs and features can be posted here