User blog comment:Hayashi H/Advanced Mechanics Guide/@comment-80.5.59.189-20151127214536/@comment-26486243-20151226102140

API call 1 is the status of Inazuma id #29011 before level up. She has 12 Firepower, 27 Torpedo, 14 AA, 6 Armour, 42 Evasion, 20 ASW, 5 LoS and 10 Luck at level 1.

{"api_id":29011,"api_sortno":74,"api_ship_id":37,"api_lv":1,"api_exp":[36,64,36],"api_nowhp":15,"api_maxhp":15,"api_leng":1,"api_slot":[42035,-1,-1,-1,-1],"api_onslot":[0,0,0,0,0],"api_slot_ex":0,"api_kyouka":[0,0,0,0,0],"api_backs":1,"api_fuel":12,"api_bull":16,"api_slotnum":2,"api_ndock_time":0,"api_ndock_item":[0,0],"api_srate":0,"api_cond":50,"api_karyoku":[12,29],"api_raisou":[27,69],"api_taiku":[14,39],"api_soukou":[6,19],"api_kaihi":[42,79],"api_taisen":[20,49],"api_sakuteki":[5,19],"api_lucky":[10,49],"api_locked":0,"api_locked_equip":0}

API call 2 is the status of Inazuma id #29011 after level up, in the middle of the sortie (from ship_deck API call). She has 12 Firepower, 28 Torpedo, 14 AA, 7 Armour, 42 Evasion, 20 ASW, 5 LoS, 10 Luck at level 2.

{"api_id":29011,"api_sortno":74,"api_ship_id":37,"api_lv":2,"api_exp":[108,192,4],"api_nowhp":15,"api_maxhp":15,"api_leng":1,"api_slot":[42035,-1,-1,-1,-1],"api_onslot":[0,0,0,0,0],"api_slot_ex":0,"api_kyouka":[0,1,0,1,0],"api_backs":1,"api_fuel":6,"api_bull":8,"api_slotnum":2,"api_ndock_time":0,"api_ndock_item":[0,0],"api_srate":0,"api_cond":40,"api_karyoku":[12,29],"api_raisou":[28,69],"api_taiku":[14,39],"api_soukou":[7,19],"api_kaihi":[42,79],"api_taisen":[20,49],"api_sakuteki":[5,19],"api_lucky":[10,49],"api_locked":0,"api_locked_equip":0}

Basically, the 1 Torpedo 1 Armour stat increases from the Level Up applied on ship_deck already, so the increase is applied immediately. No tested answer for you for Combined Fleet since there's no event on at the moment, but there's no reason for it to be any different given the game code works the same way.