Grenadier & Voltigeur point costs

[Goltron]

When taking Grenadiers/Voltigeurs (or the equavilent) in a battalion, are the listed point values for the complete company of have you to buy a regular company first that is upgraded?

I´m asking as +30 Pts for Grenadiers seems to be way to much, and the light company is also very expensive. Also, the french light infantry can take a caraibnier company at 25 pts, so maybe that should be the same for line infantry?