I mostly agree, with a little kink in the "Static comp ratio then becomes equal to 15.42 to 1", but I think it's just relative terms that I think are different. So, I'm not opposing it, just looking at it using different terms and factors. Let me take a shot:

Static compression ratio (SCR) is just that - static. It is a comparison of the swept volume from BDC to the volume at TDC in a closed cylinder. It's just a volume ratio. Once the engine is built, it never changes. Ever.

The dynamic compression ratio (DCR) is a fixed __ratio__ factor that never changes and is a calculation based on the intake closing point, as opposed to the SCR compression stroke from BDC. It is always lower than static compression ratio in our engines. The ratio never changes. Ever.

Dynamic compression (DC - __not__ ratio) is a variable and ever-changing (dynamic) level of cylinder pressure at TDC (compression). The DC can be well above both the calculated SCR and the DCR (which is always lower in our typical engines than SCR). This is where the 'magic' happens, as an engine with a 'hotter' cam and later intake valve closing (smaller DC__R__) can make more power than one with less intake valve timing (larger DC__R__).

Volumetric efficiency (VE) is the engine's ability to fill the cylinders under various conditions, and becomes the primary factor in your DC (not DCR). Due to various effects (harmonic tuning, charge mass, inertial flow, etc.), the VE can exceed 100% - meaning more air in the cylinder than would fill it by by both DCR and SCR calculation in a normally aspirated engine. This is the other factor that pumps the magic in the DC result.

So, while I generally agree, due to dynamic factors, there is no actual "static compression ratio equivalent" for boost. Apples and oranges. That's comparing a dynamic effect with a calculated ratio. Yes, twice the manifold pressure will obviously give somewhere in the very general neighborhood of twice the DC (not DCR). But, due to the different (dynamic) flows caused by the greater pressure differential, the "equivalent to SCR" is not a simple and precise single calculation. That's my only beef here. On the other hand, it does give a simplistic view of how the dynamic cylinder pressure will obviously increase with boost. So, although not very accurate, it is useful in a very general sense for point of demonstration.

This is highlighted by a common phenomenon, where doubling the manifold pressure of an engine by using boost generally results in more than double the dyno horsepower. How can that be? Dynamic effects and parasitic losses.

David