If then else on a parameter in rtf template does not work

I am currently having issues with the if-then-else logic on a parameter.

I found that if I do <?xdoxslt:ifelse ($PARAM1='Y', 'ABC', '')?>, it works fine.

However, when I do <?if: $PARAM1='Y'?>ABC<?end if?>, it does not work.

I could not use the first approach as I have more complicated logic which makes me go for the second approach.

Anyone experienced this?

Thanks.