Will 1500 grafts be sufficient to lower my hairlIne till the marking drawn if i go for 2nd session of hair transplant.

1500 grafts can cover the area you drew out on the photos, but it may not give you the density and fullness you may want.  This is something you need to discuss with your surgeon face to face.  Black or brown hair against fair skin results in higher contrast (thinner look) than light blond hair against fair skin (thicker look).  High contrast will make your the 1500 grafts look thinner than low contrast.  Your hair texture and character will also play a factor.  If you have thick coarse hair which is wavy, it will look better than thin fine straight hair.  Number of grafts matter but it is not the only factor.

45-50 grafts per cm2 will be ok for a good performance.If the area you drew on the photo is around 30cm2 then 1500 grafts is a good estimation.On the other hand for female patients frontal hair line work should always planned with more grafts per cm2 if possible.

Deciding how many grafts and how much it can be lowered is easya) measure length you want in centimetresb) measure width you want in centimetresc) Multiple length x width by the density you want to achieve (ie. 25 to 45)That's how many grafts you need!EXAMPLE 1.3 cm lowering in a zone 16 cm long at a nice density of 45 follicular units per sq cm gives:i.e 16 cm x 1.3 cm x 45 = 936You can determine how many grafts you need. Remember that much of your hair is much higher density than 45 follicular units per square cm (i.e. 60 or 70), but it's risky to try to build thicker densities because grafts might not survive.  

Each doctor has a different way of estimating the number of grafts depending on the technique theyuse for harvesting and also the one, two and three hair units that they feel comfortable using to take care of clients' needs and concerns.  From looking at your pictures, I would feel comfortable  2000 grafts would yield enough one, two and three hair units to rebuild your hairline and give a bit of density and also do a bit into your own hair.