I'm tired of any confusion of Douriki, and what it is, so I'll explain it in a way that it actually applies to the One Piece Universe and makes sense.
Douriki is nothing more than Rokushiki Potential. Lucci's Rokushiki potential total is five times stronger than that of Fukuro. People like Spandam have low physical power and low Rokushiki potential.
The stronger your physical strength is, the greater your Rokushiki potential is. However Physical Strength does not equal Rokushiki Potential. This is clearly shown in the fight between Nami and Califa, as Califa is a skilled agent with a Douriki of 630. Would you rate Nami, who lacks any physical strength or endurance in comparison to Luffy or even Usopp, with a Douriki of over 630? Logic states that she uses her intelligence, so she probably isn't any stronger than a 10 Douriki's marine (or less).
To be forward: Dourikis is NOT Power Level, nor is it Ki. All it was intended to do was to show who were the stronger opponents, and give them perspective compared to the average marine.