To be frank @Trainier , you probably need to understand more clearly what this prescription only medication does, the risks and side effects. You need to understand how the concentration builds in your system week after week and the changes it makes to your body.
Posts that may seem abrupt, or are not what you want to hear, come from a place of frustration and concern for what is a reckless suggestion. You need to understand you could do yourself harm if you decide to tweak it on the word of an similarly reckless internet stranger when you have no base knowledge to critically analyse their post which says "Yup, I did and it was fine". This medication works very different to different people, they may have been fine, you might not. You need to understand the risks you are taking which are laid out clearly in the medication instructions.
Until you do it is reckless to try playing about with what is a serious medication.
While you are learning how your body is reacting within the dosing schedule, keep reading about the medication in MN posts/facebook forums, ask questions to clarify anything you don't understand, watch videos, and once you know more then start thinking about low risk tweaks. You will pick up a lot during your first 2.5mg pen.
Example of low risk tweaks - click counting to take a lower dose, using the 5th dose and perhaps going a couple of days over the 30 days
Examples of stupid tweaks - injecting more often than the 7 day schedule regularly without discussing with your provider (especially when going up doses - someone ended up in hospital with that one), going weeks beyond the 30 day rule, not staying on a new higher dose strength for the full 4 weeks, buying dispensing tools off amazon (instead of syringes off a medical supplier), using any needle more than once.
MJ is a long journey, you have only just stepped on the path, be patient and don't start throwing the paving stones around just yet.