Paul Eggert wrote:

> Ah. Is this due to glitches when the size grows from (say) "1023 KiB" to "1.0
> MiB", or is it something else?

Assuming that's the problem, I installed the attached further patches to try to 
fix it. The gnulib update fixes an off-by-one bug I encountered in gnulib while 
testing this.