The analyzed report is slightly high and but having details on what type of leaves and analysis made, is either dry matter basis or as it basis, ll give better idea to interpret the results. 

Dear Andres Silva,

I suppose that 10% lipid content is high amounts for plant leaves. Maybe your sample includes in solvent (hexan or ethanol)  after soxhlet method in flask. You should be ensure pure fat of your sample is in flask before measurement.

That is quite high. Have you not considered applying alternative analytical method/technique to verify this?

In fact, I was performing lipid content placing sample in little bags of filter paper. I mean, I was calculating lipid content using sample weight:

Lipid content (%) = ( ( W initial - W final ) / W initial ) x 100

It was weird because I worked with other variety through the same method and result was 1.5%. I attached an image of the analysis (see the color).

Other way is calculate lipid content using weight of the flask as miss Elif said.

Thank you all for your answers. 

Dear Silva

The calculation you did [Lipid content (%) = ( ( W initial - W final ) / W initial ) x 100] is used to calculate the percentage change.

The formula for calculating crude lipid (%) is

= {Final weight of beaker (g) - Initial weight beaker (g)} / Sample weight (g) X 100

If you are using anything (Filter paper bag) in addition to sample, which could not be avoided while taking final weight, that also needs to be added to the initial weight of beaker. But it is little difficult to get an accurate weight. 

What is the reason to to keep the sample in a bag?. The bag weight would also influence the result. You can directly use sample alone.