I won a match with a bot, why did my level drop from 19k to 20k?

[ONON2013]

i won the match shouldent it increase and not decrease , (by the way if it helps the bots level was 23 cause i dont like losing)

[square_fuseki]

ranks at the start of game:

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ranks after the end of game:

[square_fuseki]

was 19k, became 19k after win (18.4 → 18.1)
was 19k, became 20k after lose (18.1 → 19.7)
was 20k, became 20k after win (19.7 → 19.6)

[BHydden]

also you are giving yourself many handicap stones against a weaker opponent, so winning gives you not many points and losing takes away considerably more points.