A couple things to keep in mind, so you feel better are
If your mod pulls amps higher than the cdr it creates more draw on the battery voltage, so the voltage will drop or sag. Once it hits the mods low voltage limit, it shuts down. All the batteries we recommend will easily handle these high wattage builds since you are not continuously firing for extended periods.
Second, high power builds generally use a very short inhale, like 2 to 3.5 seconds, which is well within your batteries limits. (limits are per Mooch stress tests, at 70A for 5 second firing with 30 seconds rest and does not exceed 100c *usually below 70c is recommended*) So even though your display might say you are pulling 42A from a 20A cell, you are only doing it for a very short time, within the batteries limits, and within safe limits allowed by your mod.
Recommended batteries are Samsung, Sony, LG High Drain 20A to 30A cells. In other words.. don't trust those rewrapped 3000Mah 35A batteries you found on ebay. They are just an over rated 20A battery, usually a factory 2nd which has failed manufacturer testing and sold in bulk for things like laptops, etc.
Basically, if your regulated mod allows it, you are fine. If the current draw is to high, the mod stops firing when the low voltage limit is reached.