Pine Script Iterator returning float values

I'm trying to develop and test the following script against ADAPERP one-minute timeframe.

In the updateMA() function, I have a for loop with iterator _group. I've commented out the array functions within the loop, as these through a pine internal compilation error. The problem seems to be that the _group iterator is a float value - you can see this in the label during execution. I've also tried a while loop, and if you uncomment the math.round function for this you can see that _group is converted to integer, but the resulting calcs for _from and _to variables still don't add up.

I have to be missing something here but just can't see it.

Any help would be appreciated.

// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © aliveZebra28942

//@version=5
strategy("MA Trend", overlay=true, margin_long=100, margin_short=100)

var MA_maxLength            =   200
var MA_maturityLength       =   MA_maxLength * 3
var MA                      =   array.new_float(7, 0.0)
var MA_order                =   array.new_float(6, 0.0)
var MA_slope                =   array.new_float(6, 0.0)
var MA_gap                  =   array.new_float(6, 0.0)
var MA_orderGroup           =   array.new_float(3, 0.0)
var MA_slopeGroup           =   array.new_float(3, 0.0)
var MA_gapGroup             =   array.new_float(3, 0.0)
MA_disp                     =   barstate.islast 

calcMAattributes(int _index) => 
    _current                =   nz(array.get(MA, _index))
    _faster                 =   nz(array.get(MA, _index-1))
    _slope                  =   (_current - _current[1]) / _current[1]
    _gap                    =   (_faster - _current) / _current
    _order                  =   _faster > _current ? 1 : _faster < _current ? -1 : 0
    array.set(MA_order, _index-1, _order)
    array.set(MA_slope, _index-1, _slope)
    array.set(MA_gap, _index-1, _gap)    

    [_order, _slope, _gap]

updateMA() =>
    var _maturity           =   0
    MA1                     =   ta.ema(close, 5)
    MA2                     =   ta.ema(close, 30)
    MA3                     =   ta.ema(close, 50)
    MA4                     =   ta.ema(close, 75)
    MA5                     =   ta.ema(close, 100)
    MA6                     =   ta.ema(close, 150)
    MA7                     =   ta.ema(close, 200)
    array.set(MA, 0, MA1)
    array.set(MA, 1, MA2)
    array.set(MA, 2, MA3)
    array.set(MA, 3, MA4)
    array.set(MA, 4, MA5)
    array.set(MA, 5, MA6)
    array.set(MA, 6, MA7)
    if MA7 > 0
        _maturity       +=  1

    if _maturity > MA_maturityLength    
        // calc order, slope, and gap for each MA and store in attribute arrays
        for i = 1 to 6 by 1
            calcMAattributes(i)
    
    // calc order, slope, and gap for each MA GROUP and store in attribute group arrays
    //_group                  =   0
    //while _group <= 2
        for _group = 0 to 2 by 1        
            // round iterator, as pine seems to have for/while bug where iterator becomes a float ?
            //_group              :=  math.round(_group)
            _inc                =   _group == 0 ? 0.001 : _group == 1 ? 0.005 : 0.01 //(_group * 0.02) + 0.02 
            _from               =   _group*2 
            _to                 =   _from + 2
            if MA_disp
                label.new(x=bar_index, y=high + 0.01 + _inc, text="group:" + str.tostring(_group) + ",inc:" + str.tostring(_inc) + ", from:" + str.tostring(_from) + ", to:" + str.tostring(_to), color=color.aqua)

            //_orderGroupTot      =   array.sum(array.slice(MA_order, _from, _to)) 
            //_slopeGroupTot      =   array.sum(array.slice(MA_slope, _from, _to)) 
            //_gapGroupTot        =   array.sum(array.slice(MA_gap, _from, _to))    
            //array.set(MA_orderGroup, _group, _orderGroupTot) 
            //array.set(MA_slopeGroup, _group, _slopeGroupTot)   
            //array.set(MA_gapGroup, _group, _gapGroupTot)     
            //_group              +=  1
            _maturity    

MA_maturity                 =   updateMA()