each rider will try a position that balances the Powe vs drag relationship. But by far the most significant factor is the power output.
We can safely assume that Lance and jan have similar power to mass ratios;
Their power vs drag tarde offs should produce similar times over the same course if their power vs mass vs drag are similar. So what factor then contributed to Lance being over 1:30 down.
Like he said, His engine was'nt producing enough power because not enough fuel (short cahin fats and sugars) was getting to the combustion chamber (muscle fibre cells) to drive the pistons (legs).
jan's position on his bike is a fixed known quantity. The only difference was power output.
I hope it's clear and not to technical.