尝试设置一个自己的全节点，同时想把solo挖矿打开，但是设置如下后，显卡挖矿发现节点下发的任务难度都是800G的，而正常矿池下发的任务难度都只有800M
想知道如何设置才能将难度下调。
# `mining_author` is the address to receive mining rewards.
# If set, `mining_type` will be "stratum" by default.
# The value is a 40-digit hex string or a valid CIP-37 base32 address.
# By default, the value is not set.
#
mining_author="my wallet"
# `mining_type` controls whether the mining process goes through the
# stratum protocol, uses CPU-mining, or disable mining.
# Possible values are "stratum", "cpu", and "disable".
# The default value is "stratum" if `mining_author` is set.
# If the value is set and not "disable", `mining_author` must be set.
#
mining_type = "stratum"
# Listen address for stratum
#
stratum_listen_address = "0.0.0.0"
# Port for stratum.
#
stratum_port = 32525
# Window size for PoW manager
#
pow_problem_window_size = 1