Coffee (Nescafe Classic) caffeine content?

I have decided to use coffee on my non-workout days instead of a PWO to save some money (it is at least twice cheaper, as well as me only needing the caffeine (and not the other ingredients - when not hitting the gym)).

I am using a 5cc scoop (from MyProtein) to measure and a scale (Salter, so should be decent, although the weights in question are rather small). Using two relatively flat scoops I am getting 3 grams of coffee. My question is how much caffeine is it approximately? I have read after Googling that 2 grams are approx 50mg of caffeine, with 3g then being 75mg - was expecting more...

Before that I have used two cutlery tea spoons and it seemed that the volume was less - I am concerned how now 2 of 5cc scoops gives only 3 grams.

For comparison, on my workout days the PWO (MyProtein Pre-Workout Blend/PULSE® V5) provides about 150mg of caffeine, and this seems to be fine after taking it in the morning and hitting the gym soon after.

I am feeling fine right now but does it seem like a decent balance of 75mg on non-workout and 150mg on workout days? My other concern is that I am calculating the coffee caffeine wrong and would hate to be wrong, upping my intake and ending up like on 400mg of caffeine. :-)

Lastly, since starting doing the following three things recently and simultaneously my appetite went down tremendously, just an anecdote: caffeine in the morning (about 100mg), chewing gum throughout the day (one at a time, ending up using a couple throughout the day - also burns like 100 calories per day?), eating a kilogram of vegetables per day (plenty of fiber - it is 9 cucumbers and 3 carrots). Just an interesting observation! I am on a cheat-day cycle and I have no problem staying 1000 under my maintenance while not being super active.