There might be several factors, but the one that I'm sure of is that I used a 3mL syringe to draw 0.2mL of Test E, and I never removed the air pocket that's inside the syringe. So I'm sure that I took less volume of oil that I intended to.
Moving forward, I'll be using a 1mL syringe on my cruise, overdraw the Test, and push the plunger to remove the air pocket. This way I can get the dose that I want.
I'm not sure if other reasons such as scar tissue or inflammation (discussed in my thread in the Steroid Lab Testing section) affect the result due to altered absorption rate. During that cruise, my VG injection is a bit painful and it's quite difficult to push the plunger.