Are you sure these stops give more 10kms eggs?
I personally dont believe it...and think we can notice patterns that are simply random/luck.
Do you know how the egg system works? The pokemon we get are not dropped based on their egg tiers aka 5km or 10km.
Instead every single pokemon has a certain chance to drop. When you spin a stop you may recieve a pokemon from the entire pool.
There are afew 'common' pokemon with the highest chance of dropping that happen to be under the 10k egg range....so it gives the feeling of more 10km egg drops and makes it seem like theres a higher chance of getting rare hatches
(in reality tho a snorlax is just as uncommon as before, technically harder as there are more pokemon in the overall pool now, lowering the chances of specific one)
The whole egg thing is just a disguise really for getting pokemon from stops, determined upon collection. We have to hatch them to reveal what they already are