Actually, not having stuff only in LFE is equally standard practice for movie mixes, because downmixes frequently just drop the LFE channel. Dolby rules say that it just gets chucked if you don't have a subwoofer, or if you're outputting to a 2-channel stereo output.You're sure this is standard practice among music 5.1 mixers? Because I would not expect it to be so among *movie* 5.1 mixers, where the LFE is specifically meant for providing loud bassy sound effects. But there, LFE parameters are standardized. I know of no such standards among music 5.1 mixers and indeed have been told that is the reason I see such variation in LFE use in music mixes.
So film mixers absolutely will be putting bass in the mains as well as the LFE, and Dolby guidelines emphasise that's important for the reason above. The vast majority of people playing DVDs or Blu-rays will be using a 2-channel downmix without LFE.
Main variability in music mixes is the LFE level - is it calibrated for playback 10dB louder than main channels like films? Rough consensus seems to be DVD-A and Blu-ray at film +10dB ("0dB" setting in many receivers), and SACD and DTS CD at equal level ("-10dB" in many receivers). You will frequently have to mess with this setting if using SACD, unless something in the chain knows to behave differently automatically (either switching LFE level for PCM versus DSD, or the SACD player itself doing an adjustment when converting to PCM).
If your system is capable of redirecting LFE to mains, doing so shouldn't appreciably alter the level. If it does, that suggests a miscalibration. (Or maybe a receiver bug).I don't know about doing this. When I first set up my system, I had the SUBWOOFER set to "none" and determined that the bass at times was way too strong with the LFE routed to the mains/fronts. (Especially material with the kick drum in the LFE.) Two problematic songs I can think of were The Stranger and 25 or 6 to 4. I've also found that setting the CENTER speaker to "none" changes the nature of the mix on some albums.
If I had to guess, I'm going to say The Stranger was on SACD, meaning if has an SACD LFE level, so receiver should be set to "LFE -10dB" for it. But you had "LFE 0dB", but had compensated by having the subwoofer 10dB lower than it should be.
Lower LFE 10dB, increase subwoofer 10dB.
(And this sort of nonsense is why mixers shouldn't be using the LFE channel!)
(Don't know about 25 or 6 to 4 - search only found a 4.0 non-LFE mix...)
Another possibility is just that your room is too boomy at the low end, and you've compensated by turning down the subwoofer. With the main speakers playing bass, you don't get that compensation. In which case - plug the speaker ports? Use some EQ?