SDFS & finding a faster way to append data to closed file

Dear all,
I am in the process of developing a datalogger that records to SDCard using SDFS.pbp
The code is working wonderfully with hardware SPI, on a PIC16F67J50.

I am apending data to a file every 10 seconds, but I wish to close the file after every samples to make sure that I don't loose the data in case of a power loss.
The problem is that when I reopen the file, and it's size is growing, it can take a significant amount of time for SDFS to recalculate the position of then end of file.
In fact, at the end of the day with a file of several MB, it can take up to 2 minutes @48MHz to reopen the file.

I was wondering if there's a way to append the data to the closed file in a faster way: I should not have to recalculate the pointer position and cluster parameters as they were known from the last write?

Any help or direction would be appreciated!