>>/40600/
Probably with some caveats. Like whom or when. Unit commanders very well may send false reports to HQ to save their own skin (no matter the outcome of the battle). Can't bath in glory if have to admit faults, and the promotion is just too precious. This can catch up with them later however, I imagine. Depending on place and time.
Medieval chronicles however may paint the picture more dark, implications of disaster or outright claiming it - well when it's about own casualties, in case of victory it's much more desirable the total destruction, or at least the decisive defeat of the enemy, while own casualties will be lighter.
But this might deserve more than my impressions how it was done and actually look into examples.