Presume they mean 2nd row up from the low side and 18th plot in from the far side if this is the case the I think the number is possibly a typo if I am reading the plot map correctly then the number in section F I think is 3210 and section T is 8356.
I presume on plot maps FS is far side NS is near side and is that the same for all the plots?
I wonder if a call to bereavement services could help us on this as they could have more info in their database.