The SHL routine is a complex account processing algorithm that gets very creative with decimal points.
An Econ Chip is an item which can be used when hijacking a Console to gain credits instead of PWR. The number of credits received is equal to 50 times the amount of PWR which would otherwise be received, including any bonus from the agent's Hacking skill level. The number of credits received is not affected by the credit multiplier.
An Econ Chip has a cooldown of 5 turns, and can only be used by an agent with at least Speed skill level 2. An Econ Chip cannot be used in combination with an Accelerator Chip to gain more credits, and cannot be used in combination with Internationale's Wireless Emitter from a distance.
Econ Chips can be bought from some Nanofabricators for 800 credits.
This trusty device has probably seen more credits run through its circuits than some small countries.
Banks' Custom Econ Chip is a unique item belonging to Archive Banks. It is equivalent to an Econ Chip, except it has a shorter cooldown of 4 turns, and no Speed skill level requirement. Its resale value is 400 credits.
Buying an Econ Chip can be viewed as a financial investment which pays for itself after a few missions, and then starts returning a profit; when using an Econ Chip, upgrading the agent's Hacking skill can also be seen as a financial investment. Both are good investments.
An Econ Chip should be used by the agent with the highest Hacking skill level who is able to use it; it is not generally worth having more than one Econ Chip. If you have an Econ Chip, it is preferable to choose Sankaku missions and Server Farms, as these have more Consoles than other missions.
There are two strategic approaches to using an Econ Chip:
The main bottleneck to using an Econ Chip more is its cooldown; especially if you go for maximum use of the Econ Chip, you will often be waiting turns sitting next to Consoles before you can use it again. The cooldown is lower if you have Torque Injectors, and can also be reduced using Archive Nika's Discharge Rerouter augment. To maximise your use of an Econ Chip, you should plan your movement so that you can get from one Console to the next by the time it cools down; for every turn that the Econ Chip isn't on cooldown but you don't use it, you'll be in the mission for that extra turn.
The downsides of using an Econ Chip are that you will have less (or no) PWR from Consoles, and that you may have to survive at high alarm levels due to its cooldown time if you want to use it many times per mission. Forgoing the opportunity to buy an Econ Chip, or using it on fewer Consoles, is advisable if you are already having problems with PWR or dealing with alerted guards.