So :

API TC = JASO FC = ISO EGC

API TC+ = JASO FD = ISO EGD

TC-W3 is an NMMA standard for 2-stroke marine engines.

It is important to note that oil designed to meet TC W3 (ashless) specifications does not protect an engine requiring API-TC (low ash).

If a can contains both API TC and TC-W3 standards, it’s not an API TC oil, but a TC-W3 ashless oil: it’s predominant.
The reverse is also true.
Using a low-ash oil in an engine designed for an ashless type oil could lead to clogged spark plugs and combustion chambers”.

Definition of API, JASO and ISO standards for 2-stroke engines in order to better understand the standards:

Oils for 2-stroke engines must meet additional requirements: high temperature, solubility in gasoline, burn without smoke or deposits-TA(TSC1),TB(TSC ), TC (TSC3).

JASO FA Original specification established to regulate lubrication, detergency, initial torque, exhaust smoke and exhaust blockage.

JASO FB: increased lubrication, increased initial torque, detergent power, exhaust smoke and exhaust system anti-lock.
( better than FA)

JASO FC: same lubrication and initial torque as FB, but with a much higher detergency level, where a higher standard is sought for smoke and exhaust blockage than FB.

JASO FD: same as FC with very high detergency recommendations.

Definition of the ISO 2-stage standard :

ISO-L-EGB: same test and requirements as JASO FB

ISO-L-EGC: same test and slightly higher detergency ( varnish,piston) than JASO FC.ISO-L-EGD: same test and same requirements as JASO FD.