How to make alevin-fry --expect cells to be better at guessing the number of cells?

[ljudevitluka]

Hi all,
I am working on the scRNAseq dataset generated with the 10x Genomics platform. We aimed to collect 10, 000 cells per experiment, and we mapped the reads to the transcriptome (since no genomic reference is available at the moment). Everything seems to be working more or less ok with alevin-fry, but in my samples, I always get the overestimation of the cell number (as per the graph bellow). I am aware we could use --force-cells, but would be more comfortable if the knee is detected by the --expect-cells flag. I tried calling --expect-cells 5000, 8000, and 10000 cells but the results were always overestimated.
My question is: Is there a way to make --expect-cells more sensitive? If I use --force-cells how will this affect my downstream analysis if some of the samples are carrying noise? If there is no automated way, is it better to take a bit of noise and hope it will get filtered out based on the further cell QC (mitoDNA genes content, ribosomal content etc.) or to be on the secure side and take a bit less cell with a risk of loss of the cells that have a lower number of genes expressed?
Thank you very much for your help and opinions :) Hopefully, this question is not out of the scope of discussion.
All the best, Luka