Lavender 40/42 essential oil is a blend of lavender oils to achieve a ratio of 40/42% linalool and linalyl acetate which are the main compounds in all lavender oils that gives it that distinct scent. Can be handy if you are a major commercial company who always want your product to smell the same.
There are so many types of lavender oil you could try though to get a stronger scent depending on your requirements and taste
Lavandula Angustifolia is the general English Lavender and it's very flowery and sweet and has no camphor and be quite gentle.
Lavandula x Intermedia which is the type of lavender grosso is also called Lavandin, is a bit stronger as it has more camphor and depending on the variety you get the camphor levels can be anywhere between 0.5-10% sometimes even stronger. This camphor most people would find makes a nicer strong lavender sent and more prefer it I have found. It has a sweet and yet spicy scent.
Lavandula Latifolia is a bit similar to the intermedia it also has a higher camphor and higher 1,8-cineole which is the main compound in eucalyptus leaves.
There are some varieties of lavender which even have camphor and 1,8-cineole close to 45% which start to take on a more eucalyptus smell about them which clears the sinuses.
Before I started farming lavender I thought they all smelt the same but each variety has it's own unique scent there are over 500 cultivars(varieties) of lavender which all have unique qualities and scents, the possibilities are endless.