Thanks again! I will try to play with the booting process to learn a bit more And also I will consider removing optify packages, though maemo-optify-runonce is considered that it is used for when you update your rootfs, to be sure that everything is optified.

Anyway, you said that in your most "normal" N900 you also have the file /usr/sbin/maemo-optify-auto-opt.sh . If it is being executed on every boot like in my N900, why in your device it is not logging anything into /var/log/maemo-optify-boottime.log? I think the calculation of the bogus number should be the same in your device as in my device.
Something should have changed in my phone in the last week because the logfile had no records from before, and now it is growing.