Upakarma kandarishi tharpanam

[KSrinivasan]

Swamin
Dasan srinivasan Pranams
Though belated this doubt came to my mind during performing kandarushi tharpanam on upakarma day.

Do persons having living parents use thilam along with atshathai during nava kandarushi tharpanam?
I felt thilam is meant for pithrus only?
request clarification
Thanks
Srinivasa dasan