Inconsistent weight readings

Hi all, a bit of understanding needed from you all. im a amateur bodybuilder (in the making ) and am doing a mass gain program to pack on a bit of size and full out my physique, ive been on 300cal surplus for 3 weeks now, weighing myself the same time (Monday Morning) every week. however im getting very inconsistent readings. i understand the first week would be a bit off due to water weight fluctuation from the intake of more food, however my readings are as follows: start weight 84kg, week 1: 88kg, week 2: 86kg, week 3: 89kg. so im struggling to make sense of this becos im needing to know what direction to take, in terms of bumping up my surplus another 200cal, or to cut down (which im not wanting to do) also, should i weigh myself the day following a weekly cheat meal? or the morning before the cheat meal(day)? when assisting with this, please understand ive been in the field of fitness and bodybuilding for about 4yrs, so i know fat gain is a given and so on, i do take weekly progress pics to assess my results and so, just need a bit of understanding on the weight readings?