Cost allocation in a product design project

Good evening to all of you,

I am looking for information or statistics on the distribution of R&D (research and development) costs in a product design project. I would like to estimate the part that could reasonably be allocated to the design work, for a product that would be manufactured in small series of 20 units, to start with.

I found an article that indicated that the distribution was generally as follows: 10% R&D, 25% production, 62% operations and support and 3% product withdrawal (see attached curves, in french). The problem is that it doesn't fit my case because there would be no operating and support costs. And for the estimation we could consider the withdrawal cost negligible.

If you had no external sources. From your personal experience: would a split of 40% R&D; 60% production seem realistic to you?

Thank you in advance for your answer,