ISIS: ip mtu different ! neighborship not formed !

If we have different mtu between two neighbors ISIS neighborship doesnt come up.
More here on CCO support forum.

However, while I was reading up for CCIE, I found a workaround.

if we leave the ip mtu to be different but change the clns mtu to match up, the ISIS neighborship comes up.

R1 s2/0 -- R2 s2/0

R1

int s2/0

mtu 17001

clns mtu 9216

R2

int s2/0

mtu 17008

clns mtu 9216