3 cm are not to be disregarded. For example, from my perspective, 178 cm I am average for where I live (in Germany) . I am below average in some northern german cities such as Hamburg and Bremen. However, at 181 cm I would be at the top 35% or even top 30% overall and also above average in the northern cities.
I would probably do 5 cm femur 4 cm tibia, ==> 5 cm with Dr Monegal internal and perhaps 4 cm with Dr. Mitkovic external and that would cost me just about 60k euro in total.