Lavender odour is an interesting one. Some therapists working in palliative care find patients and their families object to a strong smelling lavender and opt for a french officinalis distilled on the farm with the stalks with very little odour at all.
Some french lavender collected wild at high altitude has a distinctive and attractive odour and is highly prized. A lot of cheaper french lavender smells of linalool added to 'standardise' the Lavender but you can buy your french lavender angustifolia with its ester content 'stated' at 40-42%, 50-52%. A good deal of the higher altititude french angustifolia is the Mailette Clone.
Many farmers take cuttings from the stronger plants which have proved resistent to disease and this too can influence the odour profile of the crop. Some therapists like to work with artisanal distillers so they get more consistency in the lavender they work with because the majority of the french lavender is farmed cooperatively and then sent to a single point to be processed from which it goes to large companies like IFF.
The italian tuscan lavender distilled from just the flowering tops has an amazing top note which lasts for about a year making it smell similar to a Lavender absolute. Take into account natural variation in soil, climate, weather and field distillation on the farm and no wonder no Lavender smells the same. The Bulgarian however I have found to have a consistent sweet floral odour which many people prefer.
Lavender as you know is grown in many places including the UK croatia, india, china and tasmania too (which is on the same latitude as provence but 'down under'.
Lets not forget Lavandin. As a study by Jane Buckle showed its aroma assisted recovering heart surgery patients to relax just as effectively as any Lavender.
And finally those using kinesiology find when clients 'self choose' oils for their needs lavender is rarely chosen so its not the case lavender has to go in every blend. However those researching synergy note lavender can bring out the best in other oils.