I'm not sure exactly what your question is, but what you're saying seems to be correct. The plays can be very juicy, but at the same time, that means they're more likely to win.
If you didn't like playing this way, you could just change it and play the moneylines instead, most likely. Usually spreads are just conversions of the moneyline, or vice versa. If you played it this way, you would be much more likely to lose series, but your losses would also be very cheap. Keep in mind that the varied results from playing moneyline rather than puckline for underdogs was not tested and I wouldn't really recommend playing it unless you did test it.