The inventory of the inventory

After the theft, they ordered an inventory. Then they ordered an inventory of the inventory. By the third, another grenade was missing. Some clues in this case come as riddles. If one stumps you, a hint will solve it. Not every row and column has to be occupied.

Suspects

• Alcino, the sergeant who did the first inventory: He counted a thousand grenades. He rounded up.
• Bernarda, the captain who did the second inventory: She counted nine hundred and ninety-nine. She says the first one rounded up.
• Ciríaco, the lieutenant who did the third inventory: He counted nine hundred and ninety-eight. He's thinking of doing a fourth.
• Dulcídia, the storeroom clerk: She keeps the sheets from all three inventories. None of them add up, but they're very neatly filed.