

https://learn.sparkfun.com/tutorials/logic-levels/all
If i read your question correctly then you are wondering if the voltages you see are going to work for TTL devices. As you can see in the linked tutorial it is not just about nominal Vcc levels. Every chip is different. :)
It makes a lot more sense once you consider where you are starting from: a rock hurtling around the sun at breakneck speed (29.8 km/s). You can not really bullseye something when you are going almost 30 km per second sideways to it.