First up, gym machines are not reliable in terms of what they say you burn calorie wise. If you want to know what you burn, get a Heart Rate Monitor. When wearing a HRM (which themselves are not even 100% reliable- but more reliable them gym machines) I get variations on machines from the machines being 50% above to 200% above what I actually burn.
Next, don't rely on calorie burn numbers for your workout: as you do the same thing, your body becomes more efficient and learns how to burn fewer calories to do the same things: your HRM and definetly not the gym machines will not always tell you this. You think your burning 100kcals, actually you've done cycling for so long that your body is used to it, it knows how to use very little energy to do the same thing, you burn 60kcals.
Added to this, your HRM or even the gym machines will tell you your total calorie burn, not just what you burnt doing that exercise. If you were just walking around normally say shopping, you may burn 100kcals in 30 mins, you exercise you burn 300kcals in that same 30 mins- but what you need to do is subtract the 100kcals you would have burnt anyway in your normal life, result? you actually burnt 200kcals extra.
I also don't believe that the body burns anywhere near this much, I think personally (from my experience) that the body burns calories slower then we think, that a HRM reads 200kcals when infact they body has an inbuilt calorie conserver thing in and actually burns far less. Moral? don't rely on machines for calorie burn specifics: try to focus on how hard an exercise feels, how high or what degree your Heart Rate jumps about when doing interval training. (The fitter you become the higher you can get it but also the faster it falls when you do the slower intervals).
The recumbent bike?: good if you have a back injury, but I can;t get a high heart rate on that thing, I find it good to warm up on but not something thats going to be of any real use to me in terms of fitness: may be useful if your new to exercise or coming back after an injury but from what you've written about the eliptical machine, your not a beginner or injured.