Yes, there are some misconceptions. Kona measures standover at the seat / top tube junction: KONA BIKES | 2015 BIKES | TRAIL 29" HT | UNIT

Raleigh doesn't say how they measure theirs - they only give a rider height to recommended size chart (ignoring limb length): Raleigh Bicycles - Revenio 2

Trek gives a measurement to somewhere closer to the seat than the steerer tube, but doesn't quantify where: Madone 7.9 - Trek Bicycle

Giant gives a stand over height, but doesn't say where it's measured: Avail Advanced SL 0 (2015) | Giant Bicycles | United States

Specialized gives a stand over height, but doesn't say where it's measured: Specialized Bicycle Components

Felt gives a stand over height, but doesn't say where it's measured: Z2 - Felt Bicycles

Bianchi doesn't even specify a stand over height: Cortina | Bianchi USA

These are the first I looked at and they were at random. NOW do you want to tell me how consistently standover height is measured? Not a SINGLE manufacturer specified any such thing as "from the midpoint" of the top tube.