It is always an interesting execise to compare these kinds of statistics, and they often vary between the sales agent and the operator. I would say treat the above as generally fairly optimistic.
You will also have to recalculate some of the figures due to minor errors in the table - for e.g. all 109s (prior to the E model) have a basic fuel capacity of 420kgs (give or take a kg or 2). The II and the C have the option of an aux tank of capacity 120kgs, giving a total of 540 kgs on these aircraft - so delete any reference to 566 or 581kgs of fuel.
Not sure what a 'block speed' is in helicopters - but 145, possibly 150kts is balls to the wall for any 109, and is weight/conditions dependent. I would not plan any faster than 140 cruise.
So, take the 109C for example - I would offer the following figures: (with the table figures in brackets)
Max Gross: (2720) 2720 kgs
Empty Weight: (1900) 1950 would be nearer the average, so:
Useful Load: (820) 770 kgs
Max fuel weight: (581) 540 kgs - with aux tank
Payload with full fuel: (239) 230 - pilot + 1.5 pax
Fuel consuption: (185) 200 !! - you might get a kilo or 2 less at altitude - but don't bet your granny on it.
So, endurance with full fuel: (2:45) 2:00 hours only, which gives a range of 290 nm - at 145kts (not 407 nm). Naturally it does depend slightly on your calculation of 'VFR reserves'. I also have a personal in-flight minimum of 50kgs a side.
The 'A' model works out at around 1:45 endurance (no aux tank) for a range of 250nm, with pilot +3. A+ is 2:15 hours, 330nm, pilot +1. The 109E Power will fly for 2:45, 415nm with pilot +1. A Power in the real world weighs nearer 2000kgs than the 1870 in the table.
Notwithstanding the above, there is no better helicopter, if you need to move a small number of people, up to 200nm, in the shortest time, resonable comfort, any weather day or night - AND it is the best looking machine in the air.