English to Romanian Bus/Financial Insurance asigurări de viaţă

Certain impairments exhibit an extra mortality which is not a constant multiple of standard mortality but rather is independent of age. In such cases, the rating is expressed as a flat extra premium per mille of the sum insured, either permanently or for a temporary period...

Am găsit definiţia:
flat extra premium method
A method for rating substandard risks used when the extra risk is considered to be constant. The underwriter assesses a specific extra premium for each $1,000 of insurance.
http://www.accuquote.com/glossBrowse.cfm?Search=flat extra p...

Dicţionarul englez-român de asigurări, termeni juridici şi drept comercial de Dan Dumitrescu oferă traducerea flat premiums = prime constante.

Mulţumesc anticipat.