Huge misuse of stats there. Some of the 25 were last season, when he was barely out of metaphorical nappies.
This season: 18 appearances in the league, but some were as sub for a short time. It's under 14 games worth in minutes. And lot of them were in an unfamiliar position, out wide.
Look at the numbers for his 8 starts up front (on his own or with Wilson). 3 in those 8 games.
Also, look at his other contributions to scoring. Eliezer has 5 assists this season - which is 5 more than Isidor.
Sure, Mayenda should have scored more - everyone can see that he's missed chances. But the fact that he's got into scoring positions is half the battle. Experience, confidence and composure will see him put away more of them. The lad is just beginning.