Surcharge percent value, possible?

Hello,

It's possible using surcharge value in percent, in E-Commerce module?

Like:

Product variations: Price
Attribute:

• Variation: Normal portion
  • Price: 0.00 (the result price e.g.: $100)
• Variation: Small portion
  • Price: *0.75% (the result price e.g.: $75)

Thx, Paul