Connectors are not chosen based on the likelihood value. Likelihood is only used to display how likely the flow will proceed towards (based on user inputs) and it is more useful when using decisioning and adaptive models.
Here is the snippet I found in the help document.
"A likelihood is a value between 1 and 100, interpreted as an assumed or known probability associated with a flow action. For example, a likelihood of 66 on a flow action labeled Accept means that users completing an assignment linked to that flow action are expected to choose the Accept flow action two out of three times. "
Connectors are chosen based on a condition, say decision table, or a when condition, when- else (fork shape), etc.
However connectors can be selected at random by the system based on the percentage value setting of the connector. Please refer to the link below.
There is no restriction from Pega to have same likelihood. It is just the probability for the cases to go through that connector. Say 50-50 is the likelihood defined, there will be equal chances for the case to take that particular connector.
Below is the flow that I used for testing, the decision shape is a fork and all the connectors emerging out of it have the same likelihood with when conditions(named as North/South/East/West for understanding) evaluating to true at all time.
All connectors connected - got routed to assignment 4
Deleted connector(East) - got routed to assignment 2
Deleted connectors(East and North) - got routed to assignment 3
so it is kind of routing to the East connector of decision shape first and continues in anticlockwise manner till it reaches the one in the south.
Tried replacing the connector names and assignment names, got the same result.