Err dunno Marier because you haven't told us how much insulin the pump delivered ! (well saline not insulin, but what was the actual dose it calculated?)
Say your ratio was 1u to 1CP and you only had a 1u pen, you would have injected 3u as you say, because your BG was 5.0 when you started. But you've put all your carb ratios and correction ratios and what numbers you want it to correct to at each time of day, into the Settings on the pump, so the Bolus Wizard on the pump should have calculated exactly how much insulin you needed to achieve that exact level. So it would start off by saying Marier needs 3.9u of insulin, then I have to knock off the exact amount of insulin from that 3.9 u to bring her BG up to 6.5 because that's what my settings say to do. So it may tell you you need 3.2u or 2.8 or whatever it works out the answer to based on what the settings say.
Does that make any sense at all? or have I just totally confused you!