IMO, being heard is not the same as being seen. The ogre might not be able to find the character, he might think the sound was just a rat or something. That's not the same as disadvantage on a stealth check. Two rolls in this case are not always a binary pass or fail.
In addition, sneaking past a sleeping guard would require a move silently roll and not both. Special equipment like footpad boots come into play and not the character's darksuit. Of course, in 2e race, kit, class, level, dex, and equipment all factor into each roll. This means that some races and kits are better at hiding and others are better at moving silently. In this case, I think more granularity is welcomed.