As my company is not listed, the investment banks apply an illiquidity premium. Actually, they say it is an illiquidity premium but then they call it...

As my company is not listed, the investment banks apply an illiquidity premium. Actually, they say it is an illiquidity premium but then they call it a small cap premium. One of the banks, apparently based on Titman y Martin (2007), added the following small cap premiums: “0.91% if the capitalization is situated between $1,167 and $4,794 million; 1.70% if the capitalization is between $331 and $1,167 million; 4.01% if it is lower than $331 million”. Another bank adds 2% because historically the return of small companies was smaller than that of big companies. Which one is more appropriate?