Smash experiment sees no resulting surface larger than before on elipsoid

see attached, dims of rectangle and elipsoid show no flattened out surface either banana peeled Mercator style or larger.
Surely flattening out should see a larger surface and shape result ?

This was prompted to see what happened in smash by this…
In my project I opted for explode ‘no’ and the result was no larger at first glance, the triangle panel was if anything smaller, resulting panels were overlapping.

I want to supply the shape a triangle panel on a compound curved rudder surface makes to the maker, smash seemed ideal.
I opted for explode then had to joint the parts together.
Joining the triangle together saw join failures, as lines no longer join up. A retrace was necessary.

SteveSmash on compound curve puzzled.3dm (104.2 KB)

From Help:

“Since it is not possible to flatten a double-curved object (like a half a coconut shell) to get a paper pattern, the answer is always inaccurate to some degree. This command is useful if the object you are flattening is not extremely curved and you want to make the pattern out of a stretchy material like rubber.”