In general, Type=exec is superior to Type=simple. Let's not assume that
the service is started before it was really started.
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true
[Service]
ExecStart=/bin/true
-Type=simple
+Type=exec
RemainAfterExit=true